diff --git a/midi-music-box.cabal b/midi-music-box.cabal
--- a/midi-music-box.cabal
+++ b/midi-music-box.cabal
@@ -1,5 +1,5 @@
 Name:                midi-music-box
-Version:             0.0.0.2
+Version:             0.0.0.3
 Synopsis:            Convert MIDI file to music box punch tape
 Description:
   Convert MIDI file to music box punch tape for this kind of music box:
@@ -58,7 +58,7 @@
 Cabal-Version:       >=1.10
 
 Source-Repository this
-  Tag:         0.0.0.2
+  Tag:         0.0.0.3
   Type:        darcs
   Location:    http://hub.darcs.net/thielema/midi-music-box
 
diff --git a/src/Main.hs b/src/Main.hs
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -24,6 +24,7 @@
 
 import qualified Data.Map as Map; import Data.Map (Map, )
 import qualified Data.NonEmpty as NonEmpty
+import qualified Data.Monoid as Mn
 import Data.Foldable (foldMap, fold, )
 import Data.Tuple.HT (mapSnd, )
 
@@ -142,9 +143,9 @@
 instance Cmd.Parseable ZeroKey where
    parser =
       OP.option (ZeroKey <$> OP.auto)
-         (OP.long "zerokey" OP.<>
-          OP.metavar "INT" OP.<>
-          OP.value (ZeroKey 60) OP.<>
+         (OP.long "zerokey" Mn.<>
+          OP.metavar "INT" Mn.<>
+          OP.value (ZeroKey 60) Mn.<>
           OP.help "MIDI key for the lowest note line")
 
 
@@ -153,9 +154,9 @@
 instance Cmd.Parseable TimeStep where
    parser =
       OP.option (TimeStep <$> OP.auto)
-         (OP.long "timestep" OP.<>
-          OP.metavar "SECONDS" OP.<>
-          OP.value (TimeStep 0.1) OP.<>
+         (OP.long "timestep" Mn.<>
+          OP.metavar "SECONDS" Mn.<>
+          OP.value (TimeStep 0.1) Mn.<>
           OP.help "time step between lines")