diff --git a/hexpat-lens.cabal b/hexpat-lens.cabal
--- a/hexpat-lens.cabal
+++ b/hexpat-lens.cabal
@@ -1,5 +1,5 @@
 name:                hexpat-lens
-version:             0.0.3
+version:             0.0.4
 synopsis:            Lenses for Hexpat.
 license:             MIT
 license-file:        LICENSE
diff --git a/src/Text/XML/Expat/Lens.hs b/src/Text/XML/Expat/Lens.hs
--- a/src/Text/XML/Expat/Lens.hs
+++ b/src/Text/XML/Expat/Lens.hs
@@ -19,6 +19,5 @@
   
   ) where
 
-import Text.XML.Expat.Tree
 import Text.XML.Expat.Lens.Unqualified
 import Text.XML.Expat.Lens.Parse
diff --git a/src/Text/XML/Expat/Lens/Unqualified.hs b/src/Text/XML/Expat/Lens/Unqualified.hs
--- a/src/Text/XML/Expat/Lens/Unqualified.hs
+++ b/src/Text/XML/Expat/Lens/Unqualified.hs
@@ -64,12 +64,16 @@
 
 instance (GenericXMLString a, Applicative f) => Ixed f (UNode a) where
   ix = ixAt
-  
+
 instance ( GenericXMLString a
          , Applicative f
          , Contravariant f ) => Contains f (UNode a) where
   contains = containsAt
 
+instance Plated (UNode a) where
+  plate = children . traverse
+  {-# INLINE plate #-}
+
 -- | Traverses the children of an 'Element'. This is as
 -- an "Affine", or 0-or-1 target, 'Traversal'. In regex terms, you
 -- can think of it like the @?@ suffix modifier.
@@ -96,10 +100,12 @@
 -- We can use plated/uniplate lenses to traverse all of the elements of
 -- the tree in a bottom up fashion.
 
--- | Produces a list of all 'UNode's in a XML tree.
+-- | Produces a list of all 'UNode's in a XML tree. Synonym for
+-- 'universe'.
 
 allNodes :: UNode t -> [UNode t]
-allNodes = universeOf (children . traverse)
+allNodes = universe
+{-# INLINE allNodes #-}
 
 -- And if we build one sort-of @Traversal@ then we'll have replicated
 -- almost all of the functionality of @NodeClass@ in lenses. This uses
@@ -109,3 +115,15 @@
 
 named :: (Choice p, Applicative f, Eq t) => t -> Overloaded' p f (UNode t) (UNode t)
 named n = filtered (isNamed n)
+
+-- | @parameterized k v@ traverses 'Element's which match the value
+-- @v@ at the key @k@ in their attributes.
+
+parameterized :: (Choice p, Applicative f, Eq t, GenericXMLString t) =>
+                 t -> t -> Overloaded' p f (UNode t) (UNode t)
+parameterized k v = filtered check where
+  check u = case u ^? ix k . to (==v) of
+    Just True -> True
+    _         -> False
+  {-# INLINE check #-}
+{-# INLINE parameterized #-}