diff --git a/Control/Comonad/Random.hs b/Control/Comonad/Random.hs
--- a/Control/Comonad/Random.hs
+++ b/Control/Comonad/Random.hs
@@ -99,7 +99,7 @@
 
 -- | Generate an infinite list of values by applying a function
 --   repeatedly.
-extracts :: (Rand a -> Rand a) -> Rand a -> [a]
+extracts :: Copointed f => (f a -> f a) -> f a -> [a]
 extracts f = liftA2 (:) extract (extracts f . f)
 
 {- $Example
diff --git a/comonad-random.cabal b/comonad-random.cabal
--- a/comonad-random.cabal
+++ b/comonad-random.cabal
@@ -1,5 +1,5 @@
 name:                comonad-random
-version:             0.1.1
+version:             0.1.2
 synopsis:            Comonadic interface for random values
 description:         Comonadic interface for random values
 category:            Control