diff --git a/src/internal/_isTransformer.js b/src/internal/_isTransformer.js
index 1496d4b0a..87ef76fc6 100644
--- a/src/internal/_isTransformer.js
+++ b/src/internal/_isTransformer.js
@@ -1,7 +1,3 @@
-var _symTransformer = require('./_symTransformer');
-
-
 module.exports = function _isTransformer(obj) {
-    return (obj[_symTransformer] != null) ||
-        (typeof obj.step === 'function' && typeof obj.result === 'function');
+    return (typeof obj.step === 'function' && typeof obj.result === 'function');
 };
diff --git a/src/internal/_stepCat.js b/src/internal/_stepCat.js
index 38ad87017..5f0ca5733 100644
--- a/src/internal/_stepCat.js
+++ b/src/internal/_stepCat.js
@@ -1,7 +1,6 @@
 var _add = require('./_add');
 var _appendTo = require('./_appendTo');
 var _isTransformer = require('./_isTransformer');
-var _symTransformer = require('./_symTransformer');
 var isArrayLike = require('../isArrayLike');
 var merge = require('../merge');
 
@@ -38,7 +37,7 @@ module.exports = (function() {
 
   return function _stepCat(obj) {
       if (_isTransformer(obj)) {
-          return obj[_symTransformer] || obj;
+          return obj;
       }
       if (isArrayLike(obj)) {
           return _stepCatArray;
diff --git a/src/internal/_symTransformer.js b/src/internal/_symTransformer.js
deleted file mode 100644
index 7af761292..000000000
--- a/src/internal/_symTransformer.js
+++ /dev/null
@@ -1 +0,0 @@
-module.exports = (typeof Symbol !== 'undefined') ? Symbol('transformer') : '@@transformer';