diff --git a/Scripts/Node.cs b/Scripts/Node.cs
index a07679a..28e389d 100644
--- a/Scripts/Node.cs
+++ b/Scripts/Node.cs
@@ -262,7 +262,7 @@ namespace XNode {
 
 #region Attributes
         /// <summary> Mark a serializable field as an input port. You can access this through <see cref="GetInputPort(string)"/> </summary>
-        [AttributeUsage(AttributeTargets.Field, AllowMultiple = true)]
+        [AttributeUsage(AttributeTargets.Field)]
         public class InputAttribute : Attribute {
             public ShowBackingValue backingValue;
             public ConnectionType connectionType;
@@ -285,7 +285,7 @@ namespace XNode {
         }
 
         /// <summary> Mark a serializable field as an output port. You can access this through <see cref="GetOutputPort(string)"/> </summary>
-        [AttributeUsage(AttributeTargets.Field, AllowMultiple = true)]
+        [AttributeUsage(AttributeTargets.Field)]
         public class OutputAttribute : Attribute {
             public ShowBackingValue backingValue;
             public ConnectionType connectionType;