diff --git a/pipes-concurrency.cabal b/pipes-concurrency.cabal
--- a/pipes-concurrency.cabal
+++ b/pipes-concurrency.cabal
@@ -1,5 +1,5 @@
 Name: pipes-concurrency
-Version: 2.0.13
+Version: 2.0.14
 Cabal-Version: >=1.10
 Build-Type: Simple
 License: BSD3
diff --git a/src/Pipes/Concurrent.hs b/src/Pipes/Concurrent.hs
--- a/src/Pipes/Concurrent.hs
+++ b/src/Pipes/Concurrent.hs
@@ -147,14 +147,14 @@
     'fromMailbox' terminates when the 'Mailbox' source of values is exhausted.
 -}
 fromMailbox :: (MonadIO m) => Mailbox a -> Producer' a m ()
-fromMailbox = fromInput . snd
+fromMailbox (_, input) = fromInput input
 
 {-| Convert a 'Mailbox' to a 'Pipes.Consumer'
 
     'toMailbox' terminates when the 'Mailbox' sink of values is exhausted.
 -}
 toMailbox :: (MonadIO m) => Mailbox a -> Consumer' a m ()
-toMailbox = toOutput . fst
+toMailbox (output, _) = toOutput output
 
 {-| Put a value in a 'Mailbox'