diff --git a/Data/Vector/Fixed.hs b/Data/Vector/Fixed.hs
--- a/Data/Vector/Fixed.hs
+++ b/Data/Vector/Fixed.hs
@@ -17,10 +17,19 @@
     Dim
   , Z
   , S
+    -- ** Synonyms for small numerals
+  , N1
+  , N2
+  , N3
+  , N4
+  , N5
+  , N6
     -- ** Type class
   , Vector(..)
   , Arity
+  , Fun(..)
   , length
+  , convertContinuation
     -- * Generic functions
     -- ** Literal vectors
   , New
@@ -36,6 +45,7 @@
     -- ** Element access
   , head
   , tail
+  , tailWith
   , (!)
     -- ** Map
   , map
@@ -44,6 +54,7 @@
     -- ** Folding
   , foldl
   , foldl1
+  , foldM
   , sum
   , maximum
   , minimum
@@ -72,6 +83,23 @@
 -- Generic functions
 ----------------------------------------------------------------
 
+type N1 = S Z
+type N2 = S N1
+type N3 = S N2
+type N4 = S N3
+type N5 = S N4
+type N6 = S N5
+
+-- | Change continuation type.
+convertContinuation :: forall n a r. (Arity n)
+                    => (forall v. (Dim v ~ n, Vector v a) => v a -> r)
+                    -> Fun n a r
+{-# INLINE convertContinuation #-}
+convertContinuation f = fmap f g
+  where
+    g = construct :: Fun n a (VecList n a)
+
+
 -- TODO: does not fuse!
 -- | Newtype wrapper for partially constructed vectors. /n/ is number
 --   of uninitialized elements.
@@ -206,6 +234,19 @@
 {-# INLINE tailF #-}
 tailF (Fun f) = Fun (\_ -> f)
 
+-- | Continuation variant of tail. It should be used when tail of
+--   vector is immediately deconstructed with polymorphic
+--   function. For example @'sum' . 'tail'@ will fail with unhelpful
+--   error message because return value of @tail@ is polymorphic. But
+--   @'tailWith' 'sum'@ works just fine.
+tailWith :: (Arity n, Vector v a, Dim v ~ S n)
+         => (forall w. (Vector w a, Dim w ~ n) => w a -> r) -- ^ Continuation
+         -> v a                                             -- ^ Vector
+         -> r
+{-# INLINE tailWith #-}
+tailWith f v = inspectV v
+             $ tailF
+             $ convertContinuation f
 
 ----------------------------------------------------------------
 
diff --git a/fixed-vector.cabal b/fixed-vector.cabal
--- a/fixed-vector.cabal
+++ b/fixed-vector.cabal
@@ -1,5 +1,5 @@
 Name:           fixed-vector
-Version:        0.1
+Version:        0.1.1
 Synopsis:       Generic vectors with fixed length
 Description:
   Generic vectors with fixed length. Package is structured as follows:
@@ -22,6 +22,11 @@
   .
   [@Data.Vector.Fixed.Primitive@]
   Unboxed vectors based on pritimive package.
+  .
+  Changes in 0.1.1
+  .
+  * @foldM@ and @tailWith@ added. Type synonyms for numbers up to 6 are
+    added. @Fun@ is reexported from @Data.Vector.Fixed@.
 
 Cabal-Version:  >= 1.6
 License:        BSD3