diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,2 +1,6 @@
+# 0.2
+* Require GHC 7.6 or greater
+* Exposed `~>` type synonym
+
 # 0.1
 * Initial commit
diff --git a/natural-transformation.cabal b/natural-transformation.cabal
--- a/natural-transformation.cabal
+++ b/natural-transformation.cabal
@@ -1,5 +1,5 @@
 name:                natural-transformation
-version:             0.1
+version:             0.2
 synopsis:            A natural transformation package.
 description:         A natural transformation transforms a container @f a@ into another
                      container @g a@ while preserving the internal structure. Natural
@@ -24,7 +24,7 @@
 library
   exposed-modules:     Control.Natural
                        Control.Transformation
-  build-depends:       base >= 3 && < 5
+  build-depends:       base >= 4.6 && < 5
   hs-source-dirs:      src
   default-language:    Haskell2010
   ghc-options:         -Wall
@@ -32,9 +32,9 @@
 test-suite natural-transformation-properties
   type:                exitcode-stdio-1.0
   main-is:             Properties.hs
-  build-depends:       base                   >= 4.5 && < 5
+  build-depends:       base                   >= 4.6 && < 5
                      , containers             >= 0.1 && < 0.6
-                     , natural-transformation == 0.1
+                     , natural-transformation == 0.2
                      , quickcheck-instances   >= 0.1 && < 0.4
                      , tasty                  >= 0.8 && < 0.11
                      , tasty-quickcheck       >= 0.8 && < 0.9
diff --git a/src/Control/Natural.hs b/src/Control/Natural.hs
--- a/src/Control/Natural.hs
+++ b/src/Control/Natural.hs
@@ -1,23 +1,21 @@
-{-# LANGUAGE CPP, FlexibleInstances, RankNTypes, TypeFamilies, TypeOperators #-}
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE TypeOperators #-}
 
-#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 706 && MIN_VERSION_base(4,7,0)
+#if MIN_VERSION_base(4,7,0)
 # define LANGUAGE_PolyKinds
 {-# LANGUAGE PolyKinds #-}
 #endif
 
-#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 708
+#if __GLASGOW_HASKELL__ >= 708
 # define LANGUAGE_DeriveDataTypeable
 {-# LANGUAGE DeriveDataTypeable #-}
+{-# LANGUAGE Safe #-}
 #else
 {-# LANGUAGE ScopedTypeVariables #-}
-#endif
-
-#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 702
-# if defined(LANGUAGE_DeriveDataTypeable)
-{-# LANGUAGE Safe #-}
-# else
 {-# LANGUAGE Trustworthy #-}
-# endif
 #endif
 
 {-|
@@ -29,7 +27,7 @@
 
 A data type for natural transformations.
 -}
-module Control.Natural ((:~>)(..)) where
+module Control.Natural ((~>)(), (:~>)(..)) where
 
 #if defined(LANGUAGE_PolyKinds)
 import qualified Control.Category as C (Category(..))
@@ -44,9 +42,13 @@
 -- Code adapted, with permission, from Edward Kmett's @indexed@ package.
 ---------------------------------------------------------------------------
 
-infixr 0 :~>, $$
+infixr 0 ~>
 -- | A natural transformation from @f@ to @g@.
-newtype f :~> g = Nat { ($$) :: forall x. f x -> g x }
+type f ~> g = forall x. f x -> g x
+
+infixr 0 :~>, $$
+-- | A natural transformation suitable for storing in a container.
+newtype f :~> g = Nat { ($$) :: f ~> g }
 #if defined(LANGUAGE_DeriveDataTypeable)
   deriving Typeable
 #else
diff --git a/src/Control/Transformation.hs b/src/Control/Transformation.hs
--- a/src/Control/Transformation.hs
+++ b/src/Control/Transformation.hs
@@ -1,14 +1,14 @@
-{-# LANGUAGE CPP, FlexibleInstances, FunctionalDependencies,
-             MultiParamTypeClasses, TypeOperators #-}
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE FlexibleInstances #-} 
+{-# LANGUAGE FunctionalDependencies #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE Safe #-}
+{-# LANGUAGE TypeOperators #-}
 
-#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 706 && MIN_VERSION_base(4,7,0)
+#if MIN_VERSION_base(4,7,0)
 {-# LANGUAGE PolyKinds #-}
 #endif
 
-#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 702
-{-# LANGUAGE Safe #-}
-#endif
-
 {-|
 Module:      Control.Transformation
 Copyright:   (C) 2015 The University of Kansas
@@ -27,11 +27,16 @@
 -- (typically 'Functor's).
 -- 
 -- The order of arguments allows the use of @GeneralizedNewtypeDeriving@ to wrap
--- a 'Natural', but maintain the 'Transformation' constraint. Thus, '#' can be used
+-- a ':~>', but maintain the 'Transformation' constraint. Thus, @#@ can be used
 -- on abstract data types.
 class Transformation f g t | t -> f g where
     -- | The invocation method for a natural transformation.
     (#) :: t -> f a -> g a
+
+-- {-# RULES "natural free theorem" [~] 
+--     forall h (r :: (Functor f, Functor g, Transformation f g t) => t) . 
+--     fmap h . (r #) = (r #) . fmap h 
+--   #-}
 
 instance Transformation f g (f :~> g) where
     Nat f # g = f g
diff --git a/tests/Properties.hs b/tests/Properties.hs
--- a/tests/Properties.hs
+++ b/tests/Properties.hs
@@ -1,4 +1,5 @@
-{-# LANGUAGE CPP, TypeOperators #-}
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE TypeOperators #-}
 {-|
 Module:      Main
 Copyright:   (C) 2015 The University of Kansas