diff --git a/constraint-classes.cabal b/constraint-classes.cabal
--- a/constraint-classes.cabal
+++ b/constraint-classes.cabal
@@ -1,5 +1,5 @@
 name:                constraint-classes
-version:             0.1.0
+version:             0.2.0
 synopsis:            Prelude classes using ConstraintKinds
 description:         Please see README.org
 homepage:            http://github.com/guaraqe/constraint-classes#readme
@@ -14,7 +14,6 @@
 library
   hs-source-dirs:      src
   exposed-modules:     Control.ConstraintClasses
-                     , Control.ConstraintClasses.Extras
   build-depends:       base >= 4.7 && < 5
   default-language:    Haskell2010
 
diff --git a/src/Control/ConstraintClasses/Extras.hs b/src/Control/ConstraintClasses/Extras.hs
deleted file mode 100644
--- a/src/Control/ConstraintClasses/Extras.hs
+++ /dev/null
@@ -1,28 +0,0 @@
-module Control.ConstraintClasses.Extras
-       ( CZippable (..) ) where
-
-import Control.ConstraintClasses
-
-class CFunctor f => CZippable f where
-  czip :: (CFun f a, CFun f b, CFun f (a,b))
-       => f a -> f b -> f (a,b)
-
-  czipWith :: ( CFun f a
-              , CFun f b
-              , CFun f (a,b)
-              , CFun f c)
-          => (a -> b -> c) -> f a -> f b -> f c
-  czipWith f x y = cmap (uncurry f) (czip x y)
-
-  czipWith3 :: ( CFun f a
-               , CFun f b
-               , CFun f c
-               , CFun f (a,b)
-               , CFun f ((a,b),c)
-               , CFun f d )
-            => (a -> b -> c -> d) -> f a -> f b -> f c -> f d
-  czipWith3 f x y z = cmap ((uncurry . uncurry) f)
-                           (czip (czip x y) z)
-
-  czipWith4 :: (CFun f a, CFun f b, CFun f c, CFun f d, CFun f e)
-            => (a -> b -> c -> d -> e) -> f a -> f b -> f c -> f d -> f e