diff --git a/src/Control/Arrow/Free.hs b/src/Control/Arrow/Free.hs
index 3f5fa44..6d15681 100644
--- a/src/Control/Arrow/Free.hs
+++ b/src/Control/Arrow/Free.hs
@@ -11,7 +11,7 @@
 
 module Control.Arrow.Free
   ( -- * Free arrow
-    Arr (Id, Arr, Prod)
+    Arr (..)
   , arrArr
   , liftArr
   , mapArr