diff --git a/src/tink/concurrent/Mutex.hx b/src/tink/concurrent/Mutex.hx
index aa42898..3fa1a5d 100644
--- a/src/tink/concurrent/Mutex.hx
+++ b/src/tink/concurrent/Mutex.hx
@@ -46,6 +46,13 @@ abstract Mutex(Impl) {
 			static var mutex_acquire = neko.Lib.loadLazy("std","mutex_acquire",1);
 			static var mutex_try = neko.Lib.loadLazy("std","mutex_try",1);			
 		}
+	#elseif (sys && haxe4)
+		@:forward(acquire, tryAcquire, release)
+		private abstract Impl(sys.thread.Mutex) {
+			public function new() {
+				this = new sys.thread.Mutex();
+			}
+		}
 	#elseif cpp
 		private abstract Impl(Any) {
 			
diff --git a/src/tink/concurrent/Queue.hx b/src/tink/concurrent/Queue.hx
index a86a10a..e53f41c 100644
--- a/src/tink/concurrent/Queue.hx
+++ b/src/tink/concurrent/Queue.hx
@@ -34,7 +34,14 @@ abstract Queue<T>(Impl<T>) {
 			static var deque_add = neko.Lib.loadLazy("std","deque_add",2);
 			static var deque_push = neko.Lib.loadLazy("std","deque_push",2);
 			static var deque_pop = neko.Lib.loadLazy("std","deque_pop",2);
-		}
+    }
+  #elseif (sys && haxe4)
+    @:forward(push, pop, add)
+    private abstract Impl<T>(sys.thread.Deque<T>) {
+      public function new() {
+        this = new sys.thread.Deque<T>();
+      }
+    }
 	#elseif cpp
 		private abstract Impl<T>(Any) {
 			public inline function new() 
diff --git a/src/tink/concurrent/Thread.hx b/src/tink/concurrent/Thread.hx
index d784f58..9fee6a1 100644
--- a/src/tink/concurrent/Thread.hx
+++ b/src/tink/concurrent/Thread.hx
@@ -36,7 +36,15 @@ abstract Thread(Impl) from Impl {
 			static var thread_create  =  neko.Lib.load("std", "thread_create", 2);
 			static var thread_current =  neko.Lib.load("std", "thread_current", 0);
 		}
+	#elseif (sys && haxe4)
+		@:forward(create)
+		private abstract Impl(sys.thread.Thread) from sys.thread.Thread to sys.thread.Thread {
+			static public inline function getCurrent():Impl
+				return sys.thread.Thread.current();
 		
+			static public inline function create(f)
+				return sys.thread.Thread.create(f);
+		}
 	#elseif java
 	
 		private class Wrapper implements java.lang.Runnable {
diff --git a/src/tink/concurrent/Tls.hx b/src/tink/concurrent/Tls.hx
index 390e902..57eae6c 100644
--- a/src/tink/concurrent/Tls.hx
+++ b/src/tink/concurrent/Tls.hx
@@ -31,6 +31,13 @@ abstract Tls<T>(Impl<T>) from Impl<T> {
 			static var tls_set = neko.Lib.load("std","tls_set",2);
 
 		}	
+	#elseif (sys && haxe4 && !java)
+		@:forward(value)
+		private abstract Impl<T>(sys.thread.Tls<T>) from sys.thread.Tls<T> to sys.thread.Tls<T> {
+			public function new() {
+				this = new sys.thread.Tls<T>();
+			}
+		}
 	#elseif cpp
 		private abstract Impl<T>(Int) {
 			static var sFreeSlot = 0;