diff --git a/pipes-category.cabal b/pipes-category.cabal
--- a/pipes-category.cabal
+++ b/pipes-category.cabal
@@ -1,7 +1,7 @@
 name:                pipes-category
-version:             0.2.0.0
+version:             0.2.0.1
 synopsis:            Allows instances for Category, Arrow and ArrowChoice for Pipes.
-description:         Please see README.md
+description:         Allows instances for Category, Arrow and ArrowChoice for Pipes.
 homepage:            https://github.com/louispan/pipes-category#readme
 license:             BSD3
 license-file:        LICENSE
@@ -30,7 +30,7 @@
   main-is:             Spec.hs
   build-depends:       base >= 4.7 && < 5
                      , pipes >= 4 && < 5
-                     , pipes-category >= 0.1.0.0
+                     , pipes-category
                      , transformers >= 0.4 && < 0.6
                      , hspec >= 2 && < 3
   ghc-options:         -Wall -threaded -rtsopts -with-rtsopts=-N
diff --git a/src/Pipes/Shaft.hs b/src/Pipes/Shaft.hs
--- a/src/Pipes/Shaft.hs
+++ b/src/Pipes/Shaft.hs
@@ -23,10 +23,14 @@
 
 instance Monad m => Category (Shaft r m) where
   id = Shaft P.cat
+  {-# INLINABLE id #-}
+
   (Shaft a) . (Shaft b) = Shaft (b P.>-> a)
+  {-# INLINABLE (.) #-}
 
 instance Monad m => Arrow (Shaft r m) where
   arr f = Shaft (PE.arr f)
+  {-# INLINABLE arr #-}
 
   -- | Send the first component of the input through the argument arrow, and copy the rest unchanged to the output.
   -- first :: Monad m => Shaft r m b c -> Shaft r m (b, d) (c, d)
@@ -54,6 +58,7 @@
       a <- P.await
       put $ f a
       P.yield a
+  {-# INLINABLE first #-}
 
   -- | A mirror image of 'first'.
   -- second :: Monad m => Shaft r m b c -> Shaft r m (d, b) (d, c)
@@ -62,6 +67,7 @@
     P.>-> runShaft (first $ Shaft bc)
     -- P.>->  (_Unwrapping Shaft %~ first $ bc)
     P.>-> PP.map swap
+  {-# INLINABLE second #-}
 
   -- Note: The following works, but may not actually be more optimal than default (***)
   -- So maybe it's better to reduce the amount of code to maintain.
@@ -97,5 +103,10 @@
 
 instance Monad m => ArrowChoice (Shaft r m) where
   left (Shaft a) = Shaft (PE.left a)
+  {-# INLINABLE left #-}
+
   right (Shaft a) = Shaft (PE.right a)
+  {-# INLINABLE right #-}
+
   (Shaft a) +++ (Shaft b) = Shaft (a PE.+++ b)
+  {-# INLINABLE (+++) #-}