diff --git a/src/Control/Monad/Yaftee/Pipe/ByteString.hs b/src/Control/Monad/Yaftee/Pipe/ByteString.hs
--- a/src/Control/Monad/Yaftee/Pipe/ByteString.hs
+++ b/src/Control/Monad/Yaftee/Pipe/ByteString.hs
@@ -1,5 +1,5 @@
 {-# LANGUAGE ImportQualifiedPost #-}
-{-# LANGUAGE BlockArguments, OverloadedStrings #-}
+{-# LANGUAGE BlockArguments, LambdaCase, OverloadedStrings #-}
 {-# LANGUAGE ExplicitForAll #-}
 {-# LANGUAGE RequiredTypeArguments #-}
 {-# LANGUAGE DataKinds #-}
@@ -15,6 +15,10 @@
 
 	Pkg,
 
+	-- * FROM/TO
+
+	from, to,
+
 	-- * STANDARD INPUT/OUTPUT
 
 	putStr, putStr',
@@ -36,9 +40,11 @@
 import Control.Monad.Yaftee.Pipe qualified as Pipe
 import Control.Monad.Yaftee.State qualified as State
 import Control.Monad.Yaftee.IO qualified as IO
+import Control.Monad.HigherFreer qualified as F
 import Control.HigherOpenUnion qualified as U
 import Data.HigherFunctor qualified as HFunctor
 import Data.Bits
+import Data.Maybe
 import Data.Bool
 import Data.ByteString qualified as BS
 import System.IO hiding (putStr, hPutStr)
@@ -103,3 +109,15 @@
 	go n (w : ws)
 		| n > 0 = (fromIntegral w .|.) . (`shiftL` 8) <$> go (n - 1) ws
 	go _ _ = Nothing
+
+from :: U.Member Pipe.P es => Int -> BS.ByteString -> Eff.E es i BS.ByteString ()
+from _ "" = pure ()
+from n s = Pipe.yield t >> from n d
+	where (t, d) = BS.splitAt n s
+
+to :: HFunctor.Tight (U.U es) => Eff.E (Pipe.P ': es) i BS.ByteString r -> Eff.E es i o BS.ByteString
+to p = (fromJust <$>) . Pipe.run $ fromPure . snd <$> p Pipe.=$= fix \go ->
+	Pipe.isMore >>= bool (pure "") (BS.append <$> Pipe.await <*> go)
+
+fromPure :: F.H h i o a -> a
+fromPure = \case F.Pure x -> x; _ -> error "not Pure"
diff --git a/src/Control/Monad/Yaftee/Pipe/ByteString/Lazy.hs b/src/Control/Monad/Yaftee/Pipe/ByteString/Lazy.hs
--- a/src/Control/Monad/Yaftee/Pipe/ByteString/Lazy.hs
+++ b/src/Control/Monad/Yaftee/Pipe/ByteString/Lazy.hs
@@ -1,5 +1,5 @@
 {-# LANGUAGE ImportQualifiedPost #-}
-{-# LANGUAGE BlockArguments, LambdaCase #-}
+{-# LANGUAGE BlockArguments, LambdaCase, OverloadedStrings #-}
 {-# LANGUAGE ExplicitForAll #-}
 {-# LANGUAGE RequiredTypeArguments #-}
 {-# LANGUAGE KindSignatures, TypeOperators #-}
@@ -9,6 +9,10 @@
 
 module Control.Monad.Yaftee.Pipe.ByteString.Lazy (
 
+	-- * FROM/TO
+
+	from, to,
+
 	-- * HANDLE
 
 	hGet, hGet', hPutStr, hPutStr',
@@ -27,9 +31,11 @@
 import Control.Monad.Yaftee.Pipe qualified as Pipe
 import Control.Monad.Yaftee.State qualified as State
 import Control.Monad.Yaftee.IO qualified as IO
+import Control.Monad.HigherFreer qualified as F
 import Control.HigherOpenUnion qualified as U
 import Data.HigherFunctor qualified as HFunctor
 import Data.Bits
+import Data.Maybe
 import Data.Bool
 import Data.Int
 import Data.ByteString qualified as BS
@@ -93,3 +99,15 @@
 	go n (w : ws)
 		| n > 0 = (fromIntegral w .|.) . (`shiftL` 8) <$> go (n - 1) ws
 	go _ _ = Nothing
+
+from :: U.Member Pipe.P es => Int64 -> LBS.ByteString -> Eff.E es i LBS.ByteString ()
+from _ "" = pure ()
+from n s = Pipe.yield t >> from n d
+	where (t, d) = LBS.splitAt n s
+
+to :: HFunctor.Tight (U.U es) => Eff.E (Pipe.P ': es) i LBS.ByteString r -> Eff.E es i o LBS.ByteString
+to p = (fromJust <$>) . Pipe.run $ fromPure . snd <$> p Pipe.=$= fix \go ->
+	Pipe.isMore >>= bool (pure "") (LBS.append <$> Pipe.await <*> go)
+
+fromPure :: F.H h i o a -> a
+fromPure = \case F.Pure x -> x; _ -> error "not Pure"
diff --git a/yaftee-conduit-bytestring.cabal b/yaftee-conduit-bytestring.cabal
--- a/yaftee-conduit-bytestring.cabal
+++ b/yaftee-conduit-bytestring.cabal
@@ -5,7 +5,7 @@
 -- see: https://github.com/sol/hpack
 
 name:           yaftee-conduit-bytestring
-version:        0.1.0.0
+version:        0.1.0.1
 synopsis:       Yaftee Conduit tools for ByteString
 description:    Please see the README on GitHub at <https://github.com/YoshikuniJujo/yaftee-conduit-bytestring#readme>
 category:       Control
@@ -51,6 +51,7 @@
     , base >=4.7 && <5
     , bitarray-bs ==0.1.*
     , bytestring ==0.12.*
+    , higher-order-freer-monad ==0.1.*
     , higher-order-open-union ==0.1.*
     , tools-yj ==0.1.*
     , typelevel-tools-yj ==0.1.*
@@ -74,6 +75,7 @@
     , base >=4.7 && <5
     , bitarray-bs ==0.1.*
     , bytestring ==0.12.*
+    , higher-order-freer-monad ==0.1.*
     , higher-order-open-union ==0.1.*
     , tools-yj ==0.1.*
     , typelevel-tools-yj ==0.1.*