diff --git a/src/leveled_bookie.erl b/src/leveled_bookie.erl
index a609330..e0d12fa 100644
--- a/src/leveled_bookie.erl
+++ b/src/leveled_bookie.erl
@@ -185,9 +185,7 @@
 -type fold_timings() :: no_timing|#fold_timings{}.
 -type head_timings() :: no_timing|#head_timings{}.
 -type timing_types() :: head|get|put|fold.
--type key() :: binary()|string()|{binary(), binary()}.
-    % Keys SHOULD be binary()
-    % string() support is a legacy of old tests
+
 -type open_options() :: 
     %% For full description of options see ../docs/STARTUP_OPTIONS.md
     [{root_path, string()|undefined} |
@@ -302,7 +300,6 @@
             % Defaults to ?COMPRESSION_POINT
         ].
 
--export_type([key/0]).
 
 
 %%%============================================================================
@@ -363,7 +360,7 @@ book_plainstart(Opts) ->
     gen_server:start(?MODULE, [set_defaults(Opts)], []).
 
 
--spec book_tempput(pid(), key(), key(), any(), 
+-spec book_tempput(pid(), leveled_codec:key(), leveled_codec:key(), any(), 
                     leveled_codec:index_specs(), 
                     leveled_codec:tag(), integer()) -> ok|pause.
 
@@ -430,7 +427,7 @@ book_put(Pid, Bucket, Key, Object, IndexSpecs) ->
 book_put(Pid, Bucket, Key, Object, IndexSpecs, Tag) ->
     book_put(Pid, Bucket, Key, Object, IndexSpecs, Tag, infinity).
 
--spec book_put(pid(), key(), key(), any(), 
+-spec book_put(pid(), leveled_codec:key(), leveled_codec:key(), any(), 
                 leveled_codec:index_specs(), 
                 leveled_codec:tag(), infinity|integer()) -> ok|pause.
 
@@ -440,7 +437,7 @@ book_put(Pid, Bucket, Key, Object, IndexSpecs, Tag, TTL) ->
                     infinity).
 
 
--spec book_mput(pid(), list(tuple())) -> ok|pause.
+-spec book_mput(pid(), list(leveled_codec:object_spec())) -> ok|pause.
 %% @doc
 %%
 %% When the store is being run in head_only mode, batches of object specs may
@@ -453,7 +450,8 @@ book_put(Pid, Bucket, Key, Object, IndexSpecs, Tag, TTL) ->
 book_mput(Pid, ObjectSpecs) ->
     book_mput(Pid, ObjectSpecs, infinity).
 
--spec book_mput(pid(), list(tuple()), infinity|integer()) -> ok|pause.
+-spec book_mput(pid(), list(leveled_codec:object_spec()), infinity|integer())
+                                                                -> ok|pause.
 %% @doc
 %%
 %% When the store is being run in head_only mode, batches of object specs may
@@ -466,8 +464,9 @@ book_mput(Pid, ObjectSpecs) ->
 book_mput(Pid, ObjectSpecs, TTL) ->
     gen_server:call(Pid, {mput, ObjectSpecs, TTL}, infinity).
 
--spec book_delete(pid(), key(), key(), leveled_codec:index_specs()) 
-                                                                -> ok|pause.
+-spec book_delete(pid(), 
+                    leveled_codec:key(), leveled_codec:key(), 
+                    leveled_codec:index_specs()) -> ok|pause.
 
 %% @doc 
 %%
@@ -478,11 +477,15 @@ book_delete(Pid, Bucket, Key, IndexSpecs) ->
     book_put(Pid, Bucket, Key, delete, IndexSpecs, ?STD_TAG).
 
 
--spec book_get(pid(), key(), key(), leveled_codec:tag()) 
+-spec book_get(pid(), 
+                leveled_codec:key(), leveled_codec:key(), leveled_codec:tag())
                                                     -> {ok, any()}|not_found.
--spec book_head(pid(), key(), key(), leveled_codec:tag())
+-spec book_head(pid(), 
+                leveled_codec:key(), leveled_codec:key(), leveled_codec:tag())
+                                                    -> {ok, any()}|not_found.
+-spec book_headonly(pid(), 
+                    leveled_codec:key(), leveled_codec:key(), leveled_codec:key())
                                                     -> {ok, any()}|not_found.
--spec book_headonly(pid(), key(), key(), key()) -> {ok, any()}|not_found.
 
 %% @doc - GET and HEAD requests
 %%
diff --git a/src/leveled_codec.erl b/src/leveled_codec.erl
index 1f9560c..0a81d1d 100644
--- a/src/leveled_codec.erl
+++ b/src/leveled_codec.erl
@@ -81,6 +81,10 @@
 
 -type tag() :: 
         ?STD_TAG|?RIAK_TAG|?IDX_TAG|?HEAD_TAG.
+-type key() :: 
+        binary()|string()|{binary(), binary()}.
+        % Keys SHOULD be binary()
+        % string() support is a legacy of old tests
 -type sqn() ::
         % SQN of the object in the Journal
         pos_integer().
@@ -114,6 +118,10 @@
         ?INKT_STND|?INKT_TOMB|?INKT_MPUT|?INKT_KEYD.
 -type journal_key() ::
         {integer(), journal_key_tag(), ledger_key()}.
+-type object_spec_v0() ::
+        {add|remove, key(), key(), key()|null, any()}.
+-type object_spec() ::
+        object_spec_v0().
 -type compression_method() ::
         lz4|native.
 -type index_specs() ::
@@ -128,6 +136,8 @@
         :: list(integer())|false.
 
 -export_type([tag/0,
+                key/0,
+                object_spec/0,
                 segment_hash/0,
                 ledger_status/0,
                 ledger_key/0,
@@ -550,9 +560,7 @@ hash(Obj) ->
 %% @doc
 %% Convert object specs to KV entries ready for the ledger
 obj_objectspecs(ObjectSpecs, SQN, TTL) ->
-    lists:map(fun({IdxOp, Bucket, Key, SubKey, Value}) ->
-                    gen_headspec(Bucket, Key, IdxOp, SubKey, Value, SQN, TTL)
-                end,
+    lists:map(fun(ObjectSpec) -> gen_headspec(ObjectSpec, SQN, TTL) end,
                 ObjectSpecs).
 
 -spec idx_indexspecs(index_specs(), 
@@ -573,7 +581,13 @@ gen_indexspec(Bucket, Key, IdxOp, IdxField, IdxTerm, SQN, TTL) ->
     {to_ledgerkey(Bucket, Key, ?IDX_TAG, IdxField, IdxTerm),
         {SQN, Status, no_lookup, null}}.
 
-gen_headspec(Bucket, Key, IdxOp, SubKey, Value, SQN, TTL) ->
+-spec gen_headspec(object_spec(), integer(), integer()|infinity) -> ledger_kv().
+%% @doc
+%% Take an object_spec as passed in a book_mput, and convert it into to a
+%% valid ledger key and value.  Supports different shaped tuples for different
+%% versions of the object_spec
+gen_headspec({IdxOp, Bucket, Key, SubKey, Value}, SQN, TTL) ->
+    % v0 object spec
     Status = set_status(IdxOp, TTL),
     K = to_ledgerkey(Bucket, {Key, SubKey}, ?HEAD_TAG),
     {K, {SQN, Status, segment_hash(K), Value}}.