diff --git a/src/dat/controllers/factory.js b/src/dat/controllers/factory.js
index 897b267..f10cf02 100644
--- a/src/dat/controllers/factory.js
+++ b/src/dat/controllers/factory.js
@@ -38,7 +38,10 @@ define([
           if (common.isNumber(arguments[2]) && common.isNumber(arguments[3])) {
 
             // Has min and max.
-            return new NumberControllerSlider(object, property, arguments[2], arguments[3]);
+            if (common.isNumber(arguments[4])) // has step
+                return new NumberControllerSlider(object, property, arguments[2], arguments[3], arguments[4]);
+            else
+                return new NumberControllerSlider(object, property, arguments[2], arguments[3]);
 
           } else {
 
@@ -62,4 +65,4 @@ define([
 
       }
 
-    });
\ No newline at end of file
+    });