diff --git a/externs/polymer-dom-api-externs.js b/externs/polymer-dom-api-externs.js
index 2076d03f89..f85cdc2677 100644
--- a/externs/polymer-dom-api-externs.js
+++ b/externs/polymer-dom-api-externs.js
@@ -14,7 +14,7 @@
  *
  * @interface
  */
-let PolymerDomApi = function() {};
+var PolymerDomApi = function() {};
 
 /**
  * @param {?Node} node