diff --git a/fixed-generic.cabal b/fixed-generic.cabal
--- a/fixed-generic.cabal
+++ b/fixed-generic.cabal
@@ -5,7 +5,7 @@
 -- see: https://github.com/sol/hpack
 
 name:           fixed-generic
-version:        0.1.0.0
+version:        0.1.0.1
 synopsis:       Fixed-point number build on generic integral number
 description:    Please see the README on GitHub at <https://github.com/YoshikuniJujo/fixed-generic#readme>
 category:       Numeric
diff --git a/src/Data/Fixed/Generic.hs b/src/Data/Fixed/Generic.hs
--- a/src/Data/Fixed/Generic.hs
+++ b/src/Data/Fixed/Generic.hs
@@ -3,7 +3,7 @@
 {-# LANGUAGE AllowAmbiguousTypes #-}
 {-# OPTIONS_GHC -Wall -fno-warn-tabs #-}
 
-module Data.Fixed.Generic (F(..), showF) where
+module Data.Fixed.Generic (F(..), showF, changeUnit) where
 
 import GHC.Internal.Read
 import GHC.Internal.Text.ParserCombinators.ReadPrec
@@ -114,3 +114,6 @@
 	readPrec = readNumber convertF
 	readListPrec = readListPrecDefault
 	readList = readListDefault
+
+changeUnit :: F a n -> F a' n
+changeUnit (MkF a) = MkF a