diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Revision history for describe
 
+## 0.1.2.1 -- 2019-09-08
+
+* Fixed unwrapPut / serialize.
+
 ## 0.1.2.0 -- 2019-09-08
 
 * Fixed Monad instance.
diff --git a/describe.cabal b/describe.cabal
--- a/describe.cabal
+++ b/describe.cabal
@@ -3,7 +3,7 @@
 --   For further documentation, see http://haskell.org/cabal/users-guide/
 
 name:                describe
-version:             0.1.2.0
+version:             0.1.2.1
 synopsis:            Combinators for describing binary data structures
 description:         Combinators for describing binary data structures, which eliminate the boilerplate of having to write isomorphic Get and Put instances. Please see the Github page for examples.
 homepage:            https://github.com/riugabachi/describe
diff --git a/src/Data/Serialize/Descriptor.hs b/src/Data/Serialize/Descriptor.hs
--- a/src/Data/Serialize/Descriptor.hs
+++ b/src/Data/Serialize/Descriptor.hs
@@ -20,12 +20,12 @@
 unwrapGet = fst . unwrapDescriptor
 
 -- | @unwrapPut s desc@ takes the structure being described and a 'Descriptor' for it, and returns the internal 'Put' monad.
-unwrapPut :: s -> Descriptor s a -> PutM ()
-unwrapPut s = ($ s) . snd . unwrapDescriptor . (>> pure ())
+unwrapPut :: s -> Descriptor s a -> PutM a
+unwrapPut s = ($ s) . snd . unwrapDescriptor
 
 -- | Convenience function for @runPut . unwrapPut s@
 serialize :: s -> Descriptor s a -> ByteString
-serialize s = snd . runPutM . unwrapPut s . (>> pure ())
+serialize s = snd . runPutM . unwrapPut s
 
 -- | Convenience function for @flip runGet bs . unwrapGet@
 deserialize :: ByteString -> Descriptor s s -> Either String s