diff --git a/library/Potoki/Core/Produce.hs b/library/Potoki/Core/Produce.hs
--- a/library/Potoki/Core/Produce.hs
+++ b/library/Potoki/Core/Produce.hs
@@ -22,6 +22,7 @@
 import qualified Potoki.Core.Fetch as A
 import qualified Data.HashMap.Strict as B
 import qualified Data.Vector as C
+import qualified Data.Vector.Generic as GenericVector
 import qualified System.Directory as G
 import qualified Acquire.Acquire as M
 import qualified Data.ByteString.Lazy as D
@@ -105,17 +106,17 @@
     transformAcquire fetch
 
 {-# INLINE vector #-}
-vector :: Vector input -> Produce input
+vector :: GenericVector.Vector vector input => vector input -> Produce input
 vector vectorVal =
-  Produce $ M.Acquire $ do
+  Produce $ liftIO $ do
     indexRef <- newIORef 0
     let
       fetch =
         A.Fetch $ do
           indexVal <- readIORef indexRef
           writeIORef indexRef $! succ indexVal
-          return $ (C.!?) vectorVal indexVal
-      in return (fetch, return ())
+          return $ (GenericVector.!?) vectorVal indexVal
+      in return fetch
 
 {-# INLINE hashMapRows #-}
 hashMapRows :: HashMap a b -> Produce (a, b)
diff --git a/potoki-core.cabal b/potoki-core.cabal
--- a/potoki-core.cabal
+++ b/potoki-core.cabal
@@ -1,5 +1,5 @@
 name: potoki-core
-version: 2.2.14
+version: 2.2.15
 synopsis: Low-level components of "potoki"
 description:
   Provides everything required for building custom instances of