diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -3,7 +3,10 @@
 
 `hw-json-standard-cursor` is support library for `hw-json`, a succinct JSON parsing library.
 
-It uses succinct data-structures to allow traversal of large JSON strings with minimal memory overhead.
+It is used to create "interest-bits" (`*.ib.idx`) files and
+"balanced-parenthesis" (`*.bp.idx`) files.  These can then be loaded by the `hw-json`
+library to enable parsing of parts of the original JSON file without deserialising
+the entire JSON file into objects in memory.
 
 For more information see [`hw-json`](https://github.com/haskell-works/hw-json).
 
diff --git a/hw-json-standard-cursor.cabal b/hw-json-standard-cursor.cabal
--- a/hw-json-standard-cursor.cabal
+++ b/hw-json-standard-cursor.cabal
@@ -1,7 +1,7 @@
 cabal-version:  2.2
 
 name:           hw-json-standard-cursor
-version:        0.1.0.1
+version:        0.1.1.0
 synopsis:       Memory efficient JSON parser
 description:    Memory efficient JSON parser. Please see README.md
 category:       Data
diff --git a/src/HaskellWorks/Data/Json/Standard/Cursor/Fast.hs b/src/HaskellWorks/Data/Json/Standard/Cursor/Fast.hs
--- a/src/HaskellWorks/Data/Json/Standard/Cursor/Fast.hs
+++ b/src/HaskellWorks/Data/Json/Standard/Cursor/Fast.hs
@@ -7,7 +7,6 @@
   , fromString
   ) where
 
-import Data.Word
 import Foreign.ForeignPtr
 import HaskellWorks.Data.Json.Standard.Cursor.Generic
 import HaskellWorks.Data.Json.Standard.Cursor.Specific
@@ -16,7 +15,6 @@
 import qualified Data.ByteString                                      as BS
 import qualified Data.ByteString.Char8                                as BSC
 import qualified Data.ByteString.Internal                             as BSI
-import qualified Data.Vector.Storable                                 as DVS
 import qualified HaskellWorks.Data.BalancedParens.RangeMin            as RM
 import qualified HaskellWorks.Data.FromForeignRegion                  as F
 import qualified HaskellWorks.Data.Json.Standard.Cursor.Internal.IbBp as J
@@ -26,13 +24,13 @@
 instance SpecificCursor Fast where
   type CursorOf Fast = Cursor
 
-type Cursor = GenericCursor BS.ByteString CsPoppy (RM.RangeMin (DVS.Vector Word64))
+type Cursor = GenericCursor BS.ByteString CsPoppy (RM.RangeMin CsPoppy)
 
 fromByteString :: BS.ByteString -> Cursor
 fromByteString bs = GenericCursor
   { cursorText      = bs
   , interests       = makeCsPoppy ib
-  , balancedParens  = RM.mkRangeMin bp
+  , balancedParens  = RM.mkRangeMin (makeCsPoppy bp)
   , cursorRank      = 1
   }
   where J.IbBp ib bp = J.toIbBp bs