diff --git a/haskus-utils.cabal b/haskus-utils.cabal
--- a/haskus-utils.cabal
+++ b/haskus-utils.cabal
@@ -1,5 +1,5 @@
 name:                haskus-utils
-version:             1.3
+version:             1.4
 synopsis:            Haskus utility modules
 license:             BSD3
 license-file:        LICENSE
@@ -9,7 +9,7 @@
 copyright:           Sylvain Henry 2018
 category:            System
 build-type:          Simple
-cabal-version:       1.21
+cabal-version:       1.20
 
 description:
    Haskus utility modules.
@@ -45,14 +45,14 @@
       ,  containers                >= 0.5
       ,  list-t                    >= 0.4
       ,  stm                       >= 2.4
-      ,  stm-containers            >= 0.2
+      ,  stm-containers            >= 1.1
       ,  vector                    >= 0.11
       ,  transformers              >= 0.4
       ,  mtl                       >= 2.2
       ,  template-haskell          >= 2.10
       ,  file-embed                >= 0.0.10
       ,  extra                     >= 1.4
-      ,  recursion-schemes         >= 5.0
+      ,  hashable                  >= 1.2
 
   build-tools: 
   ghc-options:          -Wall
diff --git a/src/lib/Haskus/Utils/Flow.hs b/src/lib/Haskus/Utils/Flow.hs
--- a/src/lib/Haskus/Utils/Flow.hs
+++ b/src/lib/Haskus/Utils/Flow.hs
@@ -7,6 +7,8 @@
    , (<|)
    , (||>)
    , (<||)
+   , (|||>)
+   , (<|||)
    -- * Monadic/applicative operators
    , when
    , unless
@@ -20,6 +22,7 @@
    , foldM_
    , forM
    , forM_
+   , forMaybeM
    , mapM
    , mapM_
    , sequence
@@ -33,13 +36,18 @@
    , whileM
    -- * Variant based operators
    , module Haskus.Utils.Variant.Flow
+   -- * Monad transformers
+   , lift
    )
 where
 
 import Haskus.Utils.Variant
 import Haskus.Utils.Variant.Flow
 import Haskus.Utils.Monad
+import Haskus.Utils.Maybe
 
+import Control.Monad.Trans.Class (lift)
+
 -- | Apply a function
 (|>) :: a -> (a -> b) -> b
 {-# INLINE (|>) #-}
@@ -67,3 +75,21 @@
 f <|| x = fmap f x
 
 infixr 0 <||
+
+-- | Apply a function in a Functor
+(|||>) :: (Functor f, Functor g) => f (g a) -> (a -> b) -> f (g b)
+{-# INLINE (|||>) #-}
+x |||> f = fmap (fmap f) x
+
+infixl 0 |||>
+
+-- | Apply a function in a Functor
+(<|||) :: (Functor f, Functor g) => (a -> b) -> f (g a) -> f (g b)
+{-# INLINE (<|||) #-}
+f <||| x = fmap (fmap f) x
+
+infixr 0 <|||
+
+-- | Composition of catMaybes and forM
+forMaybeM :: Monad m => [a] -> (a -> m (Maybe b)) -> m [b]
+forMaybeM xs f = catMaybes <|| forM xs f
diff --git a/src/lib/Haskus/Utils/STM/TMap.hs b/src/lib/Haskus/Utils/STM/TMap.hs
--- a/src/lib/Haskus/Utils/STM/TMap.hs
+++ b/src/lib/Haskus/Utils/STM/TMap.hs
@@ -23,13 +23,15 @@
 import Prelude hiding (lookup,null)
 
 import Haskus.Utils.STM
-import qualified STMContainers.Map as SMAP
-import STMContainers.Map (Key)
+import qualified StmContainers.Map as SMAP
 import ListT (fold)
 import qualified ListT
+import Data.Hashable
 
 import Haskus.Utils.Maybe (fromJust,isJust,isNothing)
 
+type Key a = (Eq a, Hashable a)
+
 -- | STM hashmap
 type TMap a b = SMAP.Map a b
 
@@ -39,7 +41,7 @@
 
 -- | Get the number of elements in the map
 size :: TMap a b -> STM Int
-size = fold f 0 . SMAP.stream
+size = fold f 0 . SMAP.listT
    where 
       f n _ = return (n+1)
 
@@ -83,7 +85,7 @@
 
 -- | Create a list of (key,value)
 toList :: TMap a b -> STM [(a,b)]
-toList = ListT.toList . SMAP.stream
+toList = ListT.toList . SMAP.listT
 
 -- | Get values
 elems :: TMap a b -> STM [b]
diff --git a/src/lib/Haskus/Utils/STM/TSet.hs b/src/lib/Haskus/Utils/STM/TSet.hs
--- a/src/lib/Haskus/Utils/STM/TSet.hs
+++ b/src/lib/Haskus/Utils/STM/TSet.hs
@@ -3,6 +3,7 @@
 -- | STM mutable set
 module Haskus.Utils.STM.TSet
    ( TSet
+   , Element
    , null
    , size
    , member
@@ -23,13 +24,15 @@
 import Prelude hiding (lookup,null,map)
 
 import Haskus.Utils.STM
-import qualified STMContainers.Set as SSET
-import STMContainers.Set (Element)
+import qualified StmContainers.Set as SSET
 import ListT (ListT, fold)
 import qualified ListT
+import Data.Hashable
 
 import Haskus.Utils.Flow (forM_)
 
+type Element a = (Eq a, Hashable a)
+
 -- | STM Set
 type TSet a = SSET.Set a
 
@@ -39,7 +42,7 @@
 
 -- | Number of elements in the set
 size :: TSet a -> STM Int
-size = fold f 0 . SSET.stream
+size = fold f 0 . SSET.listT
    where 
       f n _ = return (n+1)
 
@@ -72,7 +75,7 @@
 
 -- | Convert a set into a list
 toList :: TSet e -> STM [e]
-toList = ListT.toList . SSET.stream
+toList = ListT.toList . SSET.listT
 
 -- | Create a set from a list
 fromList :: Element e => [e] -> STM (TSet e)
@@ -87,7 +90,7 @@
 
 -- | Get the set as a ListT stream
 stream :: TSet e -> ListT STM e
-stream = SSET.stream
+stream = SSET.listT
 
 -- | Perform a set union
 unions :: Element e => [TSet e] -> STM (TSet e)