diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,12 @@
+0.4.1
+--------------------------------------------------
+* Added `hforce`
+* Added an `NFData` instance for `(:*)` and `:|`
+* Added a rule to fuse a chain of product updates
+* Added a `Monoid` instance for `TangleT`
+* Added `(@==)`
+* `#foo` can now be overloaded as `FieldOptic "foo"`
+
 0.4
 ---------------------------------------------------
 * Added `Data.Extensible.Struct`
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -4,6 +4,6 @@
 [![Build Status](https://travis-ci.org/fumieval/extensible.svg?branch=master)](https://travis-ci.org/fumieval/extensible)
 [![Hackage](https://budueba.com/hackage/extensible)](https://hackage.haskell.org/package/extensible)
 
-This package provides extensible poly-kind records and variants.
+This package provides extensible poly-kinded records, variants and effects.
 
 Bug reports and contributions are welcome!
diff --git a/benchmarks/records.hs b/benchmarks/records.hs
--- a/benchmarks/records.hs
+++ b/benchmarks/records.hs
@@ -39,14 +39,14 @@
   <: nil
 {-# NOINLINE recB #-}
 
-data HsRec = HsRec { _hsFoo :: !(Sum Int), _hsBar :: !String, _hsBaz :: !(First Int)
-  , _hsQux :: !String
-  , _hsFooBar :: !(Sum Int, String)
-  , _hsFooBaz :: !(Sum Int, First Int)
-  , _hsFooQux :: !(Sum Int, String)
-  , _hsBarFoo :: !(String, Sum Int)
-  , _hsBarBaz :: !(String, First Int)
-  , _hsBarQux :: !(String, String)
+data HsRec = HsRec { _hsFoo :: Sum Int, _hsBar :: String, _hsBaz :: First Int
+  , _hsQux :: String
+  , _hsFooBar :: (Sum Int, String)
+  , _hsFooBaz :: (Sum Int, First Int)
+  , _hsFooQux :: (Sum Int, String)
+  , _hsBarFoo :: (String, Sum Int)
+  , _hsBarBaz :: (String, First Int)
+  , _hsBarQux :: (String, String)
   }
 makeLenses ''HsRec
 
@@ -62,10 +62,10 @@
 
 main = defaultMain
   [ bgroup "basic"
-    [ bench "view" $ whnf (view foo) recA
-    , bench "hsview" $ whnf (view hsFoo) hsRec
-    , bench "set" $ whnf (set foo 3) recB
-    , bench "hsset" $ whnf (set hsFoo 3) hsRec
+    [ bench "view" $ whnf (view foo) $! recA
+    , bench "hsview" $ whnf (view hsFoo) $! hsRec
+    , bench "set" $ whnf (set foo 3) $! recB
+    , bench "hsset" $ whnf (set hsFoo 3) $! hsRec
     ]
   , bgroup "instances"
     [ bench "mappend" $ whnf (uncurry mappend) (recA, recB)
diff --git a/examples/records.hs b/examples/records.hs
--- a/examples/records.hs
+++ b/examples/records.hs
@@ -1,9 +1,7 @@
-{-# LANGUAGE TemplateHaskell, DataKinds, TypeOperators, TypeFamilies, FlexibleContexts #-}
+{-# LANGUAGE DataKinds, TypeOperators, TypeFamilies, FlexibleContexts #-}
 import Data.Extensible
 import Control.Lens
 
-mkField "name weight price description featured quantity"
-
 type Stock c = Record '[
     "name" >: String
   , "weight" >: Float
@@ -13,23 +11,23 @@
   , "quantity" >: Int]
 
 s0 :: Num c => Stock c
-s0 = name @= "DA-192H"
-  <: weight @= 260
-  <: price @= 120
-  <: featured @= True
-  <: description @= "High-quality (24bit 192kHz), lightweight portable DAC"
-  <: quantity @= 20
+s0 = #name @= "DA-192H"
+  <: #weight @= 260
+  <: #price @= 120
+  <: #featured @= True
+  <: #description @= "High-quality (24bit 192kHz), lightweight portable DAC"
+  <: #quantity @= 20
   <: emptyRecord
 
 -- Use shrinkAssoc to permute elements
 s1 :: Num c => Stock c
 s1 = shrinkAssoc
-   $ name @= "HHP-150"
-  <: featured @= False
-  <: description @= "Premium wooden headphone"
-  <: price @= 330
-  <: quantity @= 55
-  <: weight @= 200
+   $ #name @= "HHP-150"
+  <: #featured @= False
+  <: #description @= "Premium wooden headphone"
+  <: #price @= 330
+  <: #quantity @= 55
+  <: #weight @= 200
   <: emptyRecord
 
 -- If "quantity" is missing,
@@ -39,4 +37,4 @@
 --    Couldn't match type ‘Ambiguous "quantity"’ with ‘Expecting one’
 
 printSummary :: (Associate "name" String s, Associate "description" String s) => Record s -> IO ()
-printSummary s = putStrLn $ view name s ++ ": " ++ view description s
+printSummary s = putStrLn $ view #name s ++ ": " ++ view #description s
diff --git a/extensible.cabal b/extensible.cabal
--- a/extensible.cabal
+++ b/extensible.cabal
@@ -1,5 +1,5 @@
 name:                extensible
-version:             0.4
+version:             0.4.1
 synopsis:            Extensible, efficient, optics-friendly data types and effects
 homepage:            https://github.com/fumieval/extensible
 bug-reports:         http://github.com/fumieval/extensible/issues
@@ -60,7 +60,7 @@
     , FlexibleInstances
     , PolyKinds
     , CPP
-  build-depends:       base >= 4.7 && <5
+  build-depends:       base >= 4.8 && <5
     , template-haskell
     , constraints
     , ghc-prim
diff --git a/src/Data/Extensible/Dictionary.hs b/src/Data/Extensible/Dictionary.hs
--- a/src/Data/Extensible/Dictionary.hs
+++ b/src/Data/Extensible/Dictionary.hs
@@ -17,6 +17,7 @@
 -- Also includes orphan instances.
 -----------------------------------------------------------------------
 module Data.Extensible.Dictionary (library, WrapForall, Instance1) where
+import Control.DeepSeq
 import Data.Extensible.Class
 import Data.Extensible.Product
 import Data.Extensible.Sum
@@ -53,6 +54,11 @@
     (library :: Comp Dict (Instance1 Monoid h) :* xs)
   {-# INLINE mappend #-}
 
+instance WrapForall NFData h xs => NFData (h :* xs) where
+  rnf xs = henumerateFor (Proxy :: Proxy (Instance1 NFData h)) (Proxy :: Proxy xs)
+    (\i -> deepseq (hlookup i xs)) ()
+  {-# INLINE rnf #-}
+
 instance WrapForall Show h xs => Show (h :| xs) where
   showsPrec d (EmbedAt i h) = showParen (d > 10) $ showString "EmbedAt "
     . showsPrec 11 i
@@ -70,6 +76,10 @@
     Left x -> x
     Right Refl -> views (pieceAt p) (\(Comp Dict) -> compare g h) (library :: Comp Dict (Instance1 Ord h) :* xs)
   {-# INLINE compare #-}
+
+instance WrapForall NFData h xs => NFData (h :| xs) where
+  rnf (EmbedAt i h) = views (pieceAt i) (\(Comp Dict) -> rnf h) (library :: Comp Dict (Instance1 NFData h) :* xs)
+  {-# INLINE rnf #-}
 
 -- | Forall upon a wrapper
 type WrapForall c h = Forall (Instance1 c h)
diff --git a/src/Data/Extensible/Field.hs b/src/Data/Extensible/Field.hs
--- a/src/Data/Extensible/Field.hs
+++ b/src/Data/Extensible/Field.hs
@@ -20,6 +20,7 @@
   , (@=)
   , (<@=>)
   , (@:>)
+  , (@==)
   , FieldOptic
   , FieldName
   , liftField
@@ -218,3 +219,9 @@
 (@:>) :: FieldName k -> h v -> Field h (k ':> v)
 (@:>) _ = Field
 infix 1 @:>
+
+-- | Kind-monomorphic, unwrapped version of @('@=')@
+(@==) :: FieldName (k :: Symbol) -> v -> Field Identity (k ':> v)
+(@==) = (@=)
+{-# INLINE (@==) #-}
+infix 1 @==
diff --git a/src/Data/Extensible/Label.hs b/src/Data/Extensible/Label.hs
--- a/src/Data/Extensible/Label.hs
+++ b/src/Data/Extensible/Label.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE CPP, MultiParamTypeClasses #-}
+{-# LANGUAGE CPP, TypeFamilies, MultiParamTypeClasses, UndecidableInstances, ScopedTypeVariables #-}
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 -----------------------------------------------------------------------------
 -- |
@@ -18,6 +18,8 @@
 import Data.Extensible.Field
 import Data.Proxy
 import GHC.OverloadedLabels
+import Data.Extensible.Wrapper
+import Data.Extensible.Internal.Rig
 
 instance k ~ l => IsLabel k (Proxy l) where
   fromLabel _ = Proxy
@@ -25,5 +27,13 @@
 -- | Specialised version of 'itemAssoc'.
 訊 :: Proxy k -> FieldOptic k
 訊 = itemAssoc
+
+instance (Extensible f p t
+  , Associate k v xs
+  , Labelling k p
+  , Wrapper h
+  , rep ~ Repr h v)
+  => IsLabel k (Optic' p f (t (Field h) xs) rep) where
+  fromLabel _ = itemAssoc (Proxy :: Proxy k)
 
 #endif
diff --git a/src/Data/Extensible/Product.hs b/src/Data/Extensible/Product.hs
--- a/src/Data/Extensible/Product.hs
+++ b/src/Data/Extensible/Product.hs
@@ -27,6 +27,8 @@
   , htraverse
   , htraverseWithIndex
   , hsequence
+  -- * Evaluating
+  , hforce
   -- * Update
   , haccumMap
   , haccum
@@ -74,8 +76,7 @@
 -- | Convert 'L.HList' into a product.
 fromHList :: HList.HList h xs -> h :* xs
 fromHList xs = hfrozen (newFromHList xs)
-{-# NOINLINE fromHList #-}
-{-# RULES "toHList/fromHList" forall x. toHList (fromHList x) = x #-}
+{-# INLINE fromHList #-}
 
 -- | Flipped 'hlookup'
 hindex :: h :* xs -> Membership xs x ->  h x
@@ -194,10 +195,10 @@
   => (a -> g :| xs)
   -> (forall x. Membership xs x -> g x -> h x -> h x)
   -> h :* xs -> f a -> h :* xs
-haccumMap f g p0 xs = hfrozen $ do
-  s <- thaw p0
-  mapM_ (\x -> case f x of EmbedAt i v -> get s i >>= set s i . g i v) xs
-  return s
+haccumMap f g p0 xs = hmodify
+  (\s -> mapM_ (\x -> case f x of EmbedAt i v -> get s i >>= set s i . g i v) xs)
+  p0
+{-# INLINE haccumMap #-}
 
 -- | @haccum = 'haccumMap' 'id'@
 haccum :: Foldable f
@@ -210,3 +211,8 @@
 hpartition :: (Foldable f, Generate xs) => (a -> h :| xs) -> f a -> Comp [] h :* xs
 hpartition f = haccumMap f (\_ x (Comp xs) -> Comp (x:xs)) $ hrepeat $ Comp []
 {-# INLINE hpartition #-}
+
+-- | Evaluate every element in a product.
+hforce :: h :* xs -> h :* xs
+hforce p = hfoldrWithIndex (const seq) p p
+{-# INLINE hforce #-}
diff --git a/src/Data/Extensible/Struct.hs b/src/Data/Extensible/Struct.hs
--- a/src/Data/Extensible/Struct.hs
+++ b/src/Data/Extensible/Struct.hs
@@ -30,6 +30,7 @@
   , hfoldrWithIndex
   , thaw
   , hfrozen
+  , hmodify
   , toHList) where
 
 import GHC.Prim
@@ -116,6 +117,7 @@
 
   go 0 l
   return m
+{-# NOINLINE newFromHList #-}
 
 -- | The type of extensible products.
 --
@@ -160,6 +162,8 @@
   unknownHList = unsafeCoerce#
 {-# NOINLINE toHList #-}
 
+{-# RULES "toHList/fromHList" forall x. toHList (hfrozen (newFromHList x)) = x #-}
+
 -- | Create a new 'Struct' using the contents of a product.
 newFrom :: forall g h m xs. (PrimMonad m)
   => g :* xs
@@ -199,13 +203,22 @@
 -- | Create a product from an 'ST' action which returns a 'Struct'.
 hfrozen :: (forall s. ST s (Struct s h xs)) -> h :* xs
 hfrozen m = runST $ m >>= unsafeFreeze
-{-# NOINLINE[0] hfrozen #-}
+{-# INLINE[0] hfrozen #-}
 
+hmodify :: (forall s. Struct s h xs -> ST s ()) -> h :* xs -> h :* xs
+hmodify f m = runST $ do
+  s <- thaw m
+  f s
+  unsafeFreeze s
+{-# INLINE[0] hmodify #-}
+
+{-# RULES "hmodify/batch" forall
+  (a :: forall s. Struct s h xs -> ST s ())
+  (b :: forall s. Struct s h xs -> ST s ())
+  (x :: h :* xs). hmodify b (hmodify a x) = hmodify (\s -> a s >> b s) x  #-}
+
 instance (Corepresentable p, Comonad (Corep p), Functor f) => Extensible f p (:*) where
   -- | A lens for a value in a known position.
   pieceAt i pafb = cotabulate $ \ws -> sbt (extract ws) <$> cosieve pafb (hlookup i <$> ws) where
-    sbt xs x = hfrozen $ do
-      s <- thaw xs
-      set s i x
-      return s
+    sbt xs x = hmodify (\s -> set s i x) xs
   {-# INLINE pieceAt #-}
diff --git a/src/Data/Extensible/Tangle.hs b/src/Data/Extensible/Tangle.hs
--- a/src/Data/Extensible/Tangle.hs
+++ b/src/Data/Extensible/Tangle.hs
@@ -11,6 +11,7 @@
 ------------------------------------------------------------------------
 module Data.Extensible.Tangle where
 
+import Control.Applicative
 import Control.Monad.Trans.RWS.Strict
 import Control.Monad.Trans.Class
 import Data.Extensible.Class
@@ -27,6 +28,10 @@
 
 instance MonadTrans (TangleT h xs) where
   lift = TangleT . lift
+
+instance (Monad m, Monoid a) => Monoid (TangleT h xs m a) where
+    mempty = pure mempty
+    mappend = liftA2 mappend
 
 -- | Hitch an element associated to the 'FieldName' through a wrapper.
 lasso :: forall k v m h xs. (Monad m, Associate k v xs, Wrapper h)