diff --git a/src/Definition/Availability.php b/src/Definition/Availability.php
new file mode 100644
index 000000000..558a22387
--- /dev/null
+++ b/src/Definition/Availability.php
@@ -0,0 +1,28 @@
+<?php
+/**
+ * Copyright since 2007 PrestaShop SA and Contributors
+ * PrestaShop is an International Registered Trademark & Property of PrestaShop SA
+ *
+ * NOTICE OF LICENSE
+ *
+ * This source file is subject to the Academic Free License 3.0 (AFL-3.0)
+ * that is bundled with this package in the file LICENSE.md.
+ * It is also available through the world-wide-web at this URL:
+ * https://opensource.org/licenses/AFL-3.0
+ * If you did not receive a copy of the license and are unable to
+ * obtain it through the world-wide-web, please send an email
+ * to license@prestashop.com so we can send you a copy immediately.
+ *
+ * @author    PrestaShop SA <contact@prestashop.com>
+ * @copyright Since 2007 PrestaShop SA and Contributors
+ * @license   https://opensource.org/licenses/AFL-3.0 Academic Free License 3.0 (AFL-3.0)
+ */
+
+namespace PrestaShop\Module\FacetedSearch\Definition;
+
+class Availability
+{
+    const IN_STOCK = 2;
+    const AVAILABLE = 1;
+    const NOT_AVAILABLE = 0;
+}
diff --git a/src/Filters/Block.php b/src/Filters/Block.php
index 2f31dc2db..bd411ff84 100644
--- a/src/Filters/Block.php
+++ b/src/Filters/Block.php
@@ -28,6 +28,7 @@
 use Group;
 use Manufacturer;
 use PrestaShop\Module\FacetedSearch\Adapter\InterfaceAdapter;
+use PrestaShop\Module\FacetedSearch\Definition\Availability;
 use PrestaShop\Module\FacetedSearch\Product\Search;
 use PrestaShop\PrestaShop\Core\Localization\Locale;
 use PrestaShop\PrestaShop\Core\Localization\Specification\NumberSymbolList;
@@ -435,7 +436,7 @@ private function getAvailabilitiesBlock($filter, $selectedFilters)
         $availabilityOptions = [];
         if ($this->psStockManagement) {
             $availabilityOptions = [
-                2 => [
+                Availability::IN_STOCK => [
                     'name' => $this->context->getTranslator()->trans(
                         'In stock',
                         [],
@@ -443,7 +444,7 @@ private function getAvailabilitiesBlock($filter, $selectedFilters)
                     ),
                     'nbr' => 0,
                 ],
-                1 => [
+                Availability::AVAILABLE => [
                     'name' => $this->context->getTranslator()->trans(
                         'Available',
                         [],
@@ -451,7 +452,7 @@ private function getAvailabilitiesBlock($filter, $selectedFilters)
                     ),
                     'nbr' => 0,
                 ],
-                0 => [
+                Availability::NOT_AVAILABLE => [
                     'name' => $this->context->getTranslator()->trans(
                         'Not available',
                         [],
@@ -473,7 +474,7 @@ private function getAvailabilitiesBlock($filter, $selectedFilters)
                     ],
                 ]
             );
-            $availabilityOptions[0]['nbr'] = $filteredSearchAdapter->count();
+            $availabilityOptions[Availability::NOT_AVAILABLE]['nbr'] = $filteredSearchAdapter->count();
 
             // Products in stock, or with out-of-stock ordering enabled
             $filteredSearchAdapter->addOperationsFilter(
@@ -487,7 +488,7 @@ private function getAvailabilitiesBlock($filter, $selectedFilters)
                     ],
                 ]
             );
-            $availabilityOptions[1]['nbr'] = $filteredSearchAdapter->count();
+            $availabilityOptions[Availability::AVAILABLE]['nbr'] = $filteredSearchAdapter->count();
 
             // Products in stock
             $filteredSearchAdapter->addOperationsFilter(
@@ -498,7 +499,7 @@ private function getAvailabilitiesBlock($filter, $selectedFilters)
                     ],
                 ]
             );
-            $availabilityOptions[2]['nbr'] = $filteredSearchAdapter->count();
+            $availabilityOptions[Availability::IN_STOCK]['nbr'] = $filteredSearchAdapter->count();
 
             // If some filter was selected, we want to show only this single filter, it does not make sense to show others
             if (isset($selectedFilters['availability'])) {
@@ -513,8 +514,8 @@ private function getAvailabilitiesBlock($filter, $selectedFilters)
             // Hide Available option if the count is the same as In stock, it doesn't make no sense
             // Product count is a reliable indicator here, because there can never be product IN STOCK that is not AVAILABLE
             // So if the counts match, it MUST BE the same products
-            if ($availabilityOptions[1]['nbr'] == $availabilityOptions[2]['nbr']) {
-                unset($availabilityOptions[1]);
+            if ($availabilityOptions[Availability::AVAILABLE]['nbr'] == $availabilityOptions[Availability::IN_STOCK]['nbr']) {
+                unset($availabilityOptions[Availability::AVAILABLE]);
             }
         }
 
diff --git a/src/Filters/Converter.php b/src/Filters/Converter.php
index 3650b6a70..abe255c03 100644
--- a/src/Filters/Converter.php
+++ b/src/Filters/Converter.php
@@ -25,6 +25,7 @@
 use Context;
 use Db;
 use Manufacturer;
+use PrestaShop\Module\FacetedSearch\Definition\Availability;
 use PrestaShop\Module\FacetedSearch\Filters;
 use PrestaShop\Module\FacetedSearch\URLSerializer;
 use PrestaShop\PrestaShop\Core\Product\Search\Facet;
@@ -257,7 +258,7 @@ public function createFacetedSearchFiltersFromQuery(ProductSearchQuery $query)
         $searchFilters = [];
 
         // Get filters configured in module settings for the current query
-        $filters = $this->provider->getFiltersForQuery($query, $idShop);
+        $configuredFilters = $this->provider->getFiltersForQuery($query, $idShop);
 
         /*
          * Parses submitted encoded facets from (URL) string into a nice array.
@@ -266,16 +267,16 @@ public function createFacetedSearchFiltersFromQuery(ProductSearchQuery $query)
          * work very well, because there could be duplicate values for both facet and filter.
          * For example, if there are two features, feature values or categories with the same name.
          */
-        $facetAndFiltersLabels = $this->urlSerializer->unserialize($query->getEncodedFacets());
+        $receivedFilters = $this->urlSerializer->unserialize($query->getEncodedFacets());
 
         // Go through filters that are configured and find out which should be activated,
         // depending on what was provided in the encodedFacets.
-        foreach ($filters as $filter) {
+        foreach ($configuredFilters as $filter) {
             $filterLabel = $this->convertFilterTypeToLabel($filter['type']);
 
             switch ($filter['type']) {
                 case self::TYPE_MANUFACTURER:
-                    if (!isset($facetAndFiltersLabels[$filterLabel])) {
+                    if (!isset($receivedFilters[$filterLabel])) {
                         // No need to filter if no information
                         continue 2;
                     }
@@ -283,13 +284,13 @@ public function createFacetedSearchFiltersFromQuery(ProductSearchQuery $query)
                     $manufacturers = Manufacturer::getManufacturers(false, $idLang);
                     $searchFilters[$filter['type']] = [];
                     foreach ($manufacturers as $manufacturer) {
-                        if (in_array($manufacturer['name'], $facetAndFiltersLabels[$filterLabel])) {
+                        if (in_array($manufacturer['name'], $receivedFilters[$filterLabel])) {
                             $searchFilters[$filter['type']][$manufacturer['name']] = $manufacturer['id_manufacturer'];
                         }
                     }
                     break;
                 case self::TYPE_AVAILABILITY:
-                    if (!isset($facetAndFiltersLabels[$filterLabel])) {
+                    if (!isset($receivedFilters[$filterLabel])) {
                         // No need to filter if no information
                         continue 2;
                     }
@@ -299,28 +300,28 @@ public function createFacetedSearchFiltersFromQuery(ProductSearchQuery $query)
                             'Not available',
                             [],
                             'Modules.Facetedsearch.Shop'
-                        ) => 0,
+                        ) => Availability::NOT_AVAILABLE,
                         $this->context->getTranslator()->trans(
                             'Available',
                             [],
                             'Modules.Facetedsearch.Shop'
-                        ) => 1,
+                        ) => Availability::AVAILABLE,
                         $this->context->getTranslator()->trans(
                             'In stock',
                             [],
                             'Modules.Facetedsearch.Shop'
-                        ) => 2,
+                        ) => Availability::IN_STOCK,
                     ];
 
                     $searchFilters[$filter['type']] = [];
                     foreach ($quantityArray as $quantityName => $quantityId) {
-                        if (isset($facetAndFiltersLabels[$filterLabel]) && in_array($quantityName, $facetAndFiltersLabels[$filterLabel])) {
+                        if (isset($receivedFilters[$filterLabel]) && in_array($quantityName, $receivedFilters[$filterLabel])) {
                             $searchFilters[$filter['type']][] = $quantityId;
                         }
                     }
                     break;
                 case self::TYPE_CONDITION:
-                    if (!isset($facetAndFiltersLabels[$filterLabel])) {
+                    if (!isset($receivedFilters[$filterLabel])) {
                         // No need to filter if no information
                         continue 2;
                     }
@@ -345,7 +346,7 @@ public function createFacetedSearchFiltersFromQuery(ProductSearchQuery $query)
 
                     $searchFilters[$filter['type']] = [];
                     foreach ($conditionArray as $conditionName => $conditionId) {
-                        if (isset($facetAndFiltersLabels[$filterLabel]) && in_array($conditionName, $facetAndFiltersLabels[$filterLabel])) {
+                        if (isset($receivedFilters[$filterLabel]) && in_array($conditionName, $receivedFilters[$filterLabel])) {
                             $searchFilters[$filter['type']][] = $conditionId;
                         }
                     }
@@ -357,10 +358,10 @@ public function createFacetedSearchFiltersFromQuery(ProductSearchQuery $query)
                             continue;
                         }
 
-                        if (isset($facetAndFiltersLabels[$feature['url_name']])) {
-                            $featureValueLabels = $facetAndFiltersLabels[$feature['url_name']];
-                        } elseif (isset($facetAndFiltersLabels[$feature['name']])) {
-                            $featureValueLabels = $facetAndFiltersLabels[$feature['name']];
+                        if (isset($receivedFilters[$feature['url_name']])) {
+                            $featureValueLabels = $receivedFilters[$feature['url_name']];
+                        } elseif (isset($receivedFilters[$feature['name']])) {
+                            $featureValueLabels = $receivedFilters[$feature['name']];
                         } else {
                             continue;
                         }
@@ -382,10 +383,10 @@ public function createFacetedSearchFiltersFromQuery(ProductSearchQuery $query)
                             continue;
                         }
 
-                        if (isset($facetAndFiltersLabels[$attributeGroup['url_name']])) {
-                            $attributeLabels = $facetAndFiltersLabels[$attributeGroup['url_name']];
-                        } elseif (isset($facetAndFiltersLabels[$attributeGroup['attribute_group_name']])) {
-                            $attributeLabels = $facetAndFiltersLabels[$attributeGroup['attribute_group_name']];
+                        if (isset($receivedFilters[$attributeGroup['url_name']])) {
+                            $attributeLabels = $receivedFilters[$attributeGroup['url_name']];
+                        } elseif (isset($receivedFilters[$attributeGroup['attribute_group_name']])) {
+                            $attributeLabels = $receivedFilters[$attributeGroup['attribute_group_name']];
                         } else {
                             continue;
                         }
@@ -402,8 +403,8 @@ public function createFacetedSearchFiltersFromQuery(ProductSearchQuery $query)
                     break;
                 case self::TYPE_PRICE:
                 case self::TYPE_WEIGHT:
-                    if (isset($facetAndFiltersLabels[$filterLabel])) {
-                        $filters = $facetAndFiltersLabels[$filterLabel];
+                    if (isset($receivedFilters[$filterLabel])) {
+                        $filters = $receivedFilters[$filterLabel];
                         if (isset($filters[1]) && isset($filters[2])) {
                             $from = $filters[1];
                             $to = $filters[2];
@@ -413,8 +414,8 @@ public function createFacetedSearchFiltersFromQuery(ProductSearchQuery $query)
                     }
                     break;
                 case self::TYPE_CATEGORY:
-                    if (isset($facetAndFiltersLabels[$filterLabel])) {
-                        foreach ($facetAndFiltersLabels[$filterLabel] as $queryFilter) {
+                    if (isset($receivedFilters[$filterLabel])) {
+                        foreach ($receivedFilters[$filterLabel] as $queryFilter) {
                             /*
                              * This works only for categories that are child of the category we are browsing (or home category).
                              * Categories deeper in the tree will never be found. This could be fixed by providing a unique ID
@@ -428,8 +429,8 @@ public function createFacetedSearchFiltersFromQuery(ProductSearchQuery $query)
                     }
                     break;
                 default:
-                    if (isset($facetAndFiltersLabels[$filterLabel])) {
-                        foreach ($facetAndFiltersLabels[$filterLabel] as $queryFilter) {
+                    if (isset($receivedFilters[$filterLabel])) {
+                        foreach ($receivedFilters[$filterLabel] as $queryFilter) {
                             $searchFilters[$filter['type']][] = $queryFilter;
                         }
                     }
diff --git a/src/Product/Search.php b/src/Product/Search.php
index 79fc538d0..c61013bba 100644
--- a/src/Product/Search.php
+++ b/src/Product/Search.php
@@ -27,6 +27,7 @@
 use Group;
 use PrestaShop\Module\FacetedSearch\Adapter\AbstractAdapter;
 use PrestaShop\Module\FacetedSearch\Adapter\MySQL as MySQLAdapter;
+use PrestaShop\Module\FacetedSearch\Definition\Availability;
 use PrestaShop\PrestaShop\Core\Product\Search\ProductSearchQuery;
 
 class Search
@@ -192,13 +193,13 @@ private function addSearchFilters($selectedFilters)
                     // Simple cases with 1 option selected
                     if (count($filterValues) == 1) {
                         // Not available
-                        if ($filterValues[0] == 0) {
+                        if ($filterValues[0] == Availability::NOT_AVAILABLE) {
                             $operationsFilter[] = [
                                 ['quantity', [0], '<='],
                                 ['out_of_stock', $this->psOrderOutOfStock ? [0] : [0, 2], '='],
                             ];
                         // Available
-                        } elseif ($filterValues[0] == 1) {
+                        } elseif ($filterValues[0] == Availability::AVAILABLE) {
                             $operationsFilter[] = [
                                 ['out_of_stock', $this->psOrderOutOfStock ? [1, 2] : [1], '='],
                             ];
@@ -206,7 +207,7 @@ private function addSearchFilters($selectedFilters)
                                 ['quantity', [0], '>'],
                             ];
                         // In stock
-                        } elseif ($filterValues[0] == 2) {
+                        } elseif ($filterValues[0] == Availability::IN_STOCK) {
                             $operationsFilter[] = [
                                 ['quantity', [0], '>'],
                             ];
@@ -214,10 +215,10 @@ private function addSearchFilters($selectedFilters)
                         // Cases with 2 options selected
                     } elseif (count($filterValues) == 2) {
                         // Not available and available, we show everything
-                        if (in_array(0, $filterValues) && in_array(1, $filterValues)) {
+                        if (in_array(Availability::NOT_AVAILABLE, $filterValues) && in_array(Availability::AVAILABLE, $filterValues)) {
                             break;
                         // Not available or in stock
-                        } elseif (in_array(0, $filterValues) && in_array(2, $filterValues)) {
+                        } elseif (in_array(Availability::NOT_AVAILABLE, $filterValues) && in_array(Availability::IN_STOCK, $filterValues)) {
                             $operationsFilter[] = [
                                 ['quantity', [0], '<='],
                                 ['out_of_stock', $this->psOrderOutOfStock ? [0] : [0, 2], '='],
@@ -226,7 +227,7 @@ private function addSearchFilters($selectedFilters)
                                 ['quantity', [0], '>'],
                             ];
                         // Available or in stock
-                        } elseif (in_array(1, $filterValues) && in_array(2, $filterValues)) {
+                        } elseif (in_array(Availability::AVAILABLE, $filterValues) && in_array(Availability::IN_STOCK, $filterValues)) {
                             $operationsFilter[] = [
                                 ['out_of_stock', $this->psOrderOutOfStock ? [1, 2] : [1], '='],
                             ];
diff --git a/tests/php/FacetedSearch/Filters/BlockTest.php b/tests/php/FacetedSearch/Filters/BlockTest.php
index e803b950c..4cc5f382c 100644
--- a/tests/php/FacetedSearch/Filters/BlockTest.php
+++ b/tests/php/FacetedSearch/Filters/BlockTest.php
@@ -29,6 +29,7 @@
 use Mockery;
 use Mockery\Adapter\Phpunit\MockeryTestCase;
 use PrestaShop\Module\FacetedSearch\Adapter\MySQL;
+use PrestaShop\Module\FacetedSearch\Definition\Availability;
 use PrestaShop\Module\FacetedSearch\Filters\Block;
 use PrestaShop\Module\FacetedSearch\Filters\DataAccessor;
 use PrestaShop\Module\FacetedSearch\Filters\Provider;
@@ -380,16 +381,16 @@ public function testGetFiltersBlockWithQuantities()
                         'id_key' => 0,
                         'name' => 'Availability',
                         'values' => [
-                            2 => [
+                            Availability::IN_STOCK => [
                                 'name' => 'In stock',
                                 'nbr' => 50,
                             ],
-                            1 => [
+                            Availability::AVAILABLE => [
                                 'name' => 'Available',
                                 'nbr' => 100,
                                 'checked' => true,
                             ],
-                            0 => [
+                            Availability::NOT_AVAILABLE => [
                                 'name' => 'Not available',
                                 'nbr' => 1000,
                             ],
@@ -403,7 +404,7 @@ public function testGetFiltersBlockWithQuantities()
                 10,
                 [
                     'availability' => [
-                        1,
+                        Availability::AVAILABLE,
                     ],
                 ]
             )
diff --git a/tests/php/FacetedSearch/Product/SearchTest.php b/tests/php/FacetedSearch/Product/SearchTest.php
index 65a7e200f..ac6ad153a 100644
--- a/tests/php/FacetedSearch/Product/SearchTest.php
+++ b/tests/php/FacetedSearch/Product/SearchTest.php
@@ -27,6 +27,7 @@
 use Mockery;
 use Mockery\Adapter\Phpunit\MockeryTestCase;
 use PrestaShop\Module\FacetedSearch\Adapter\MySQL;
+use PrestaShop\Module\FacetedSearch\Definition\Availability;
 use PrestaShop\Module\FacetedSearch\Product\Search;
 use PrestaShop\PrestaShop\Core\Product\Search\ProductSearchQuery;
 use stdClass;
@@ -291,7 +292,7 @@ public function testInitSearchWithAllFilters()
                     [6],
                 ],
                 'availability' => [
-                    0,
+                    Availability::NOT_AVAILABLE,
                 ],
                 'weight' => [
                     '10',
@@ -636,7 +637,7 @@ public function testInitSearchWithQuantityFiltersWithoutStockManagement()
             ->andReturn('category');
         $this->search->setQuery($query);
 
-        $this->search->initSearch(['availability' => [0]]);
+        $this->search->initSearch(['availability' => [Availability::NOT_AVAILABLE]]);
 
         $this->assertEquals([], $this->search->getSearchAdapter()->getFilters()->toArray());
         $this->assertEquals([], $this->search->getSearchAdapter()->getOperationsFilters()->toArray());
@@ -686,7 +687,7 @@ public function testInitSearchWithQuantityFiltersWithoutStockManagement()
 
     public function testInitSearchWithFirstQuantityFilters()
     {
-        $this->search->initSearch(['availability' => [1]]);
+        $this->search->initSearch(['availability' => [Availability::AVAILABLE]]);
 
         $this->assertEquals([], $this->search->getSearchAdapter()->getFilters()->toArray());
         $this->assertEquals([], $this->search->getSearchAdapter()->getOperationsFilters()->toArray());
@@ -720,7 +721,7 @@ public function testInitSearchWithFirstQuantityFilters()
 
     public function testInitSearchWithSecondQuantityFilters()
     {
-        $this->search->initSearch(['availability' => [2]]);
+        $this->search->initSearch(['availability' => [Availability::IN_STOCK]]);
 
         $this->assertEquals([], $this->search->getSearchAdapter()->getFilters()->toArray());
         $this->assertEquals([], $this->search->getSearchAdapter()->getOperationsFilters()->toArray());
@@ -750,7 +751,7 @@ public function testInitSearchWithoutGroupFeature()
 
         Group::setStaticExpectations($groupMock);
 
-        $this->search->initSearch(['availability' => [2]]);
+        $this->search->initSearch(['availability' => [Availability::IN_STOCK]]);
 
         $this->assertEquals([], $this->search->getSearchAdapter()->getFilters()->toArray());
         $this->assertEquals([], $this->search->getSearchAdapter()->getOperationsFilters()->toArray());
@@ -798,7 +799,7 @@ public function testInitSearchWithUserBelongingToGroups()
 
         FrontController::setStaticExpectations($frontControllerMock);
 
-        $this->search->initSearch(['availability' => [2]]);
+        $this->search->initSearch(['availability' => [Availability::IN_STOCK]]);
 
         $this->assertEquals([], $this->search->getSearchAdapter()->getFilters()->toArray());
         $this->assertEquals([], $this->search->getSearchAdapter()->getOperationsFilters()->toArray());