diff --git a/src/Network/Ethereum/Web3.hs b/src/Network/Ethereum/Web3.hs
--- a/src/Network/Ethereum/Web3.hs
+++ b/src/Network/Ethereum/Web3.hs
@@ -29,6 +29,7 @@
   , EventAction(..)
   , Event(..)
   , Method(..)
+  , NoMethod(..)
   , nopay
   -- ** Ethereum data types
   , BytesN(..)
diff --git a/src/Network/Ethereum/Web3/Contract.hs b/src/Network/Ethereum/Web3/Contract.hs
--- a/src/Network/Ethereum/Web3/Contract.hs
+++ b/src/Network/Ethereum/Web3/Contract.hs
@@ -29,6 +29,7 @@
     EventAction(..)
   , Method(..)
   , Event(..)
+  , NoMethod(..)
   , nopay
   ) where
 
@@ -146,3 +147,12 @@
 nopay :: Wei
 {-# INLINE nopay #-}
 nopay = 0
+
+-- | Dummy method for sending transaction without method call
+data NoMethod = NoMethod
+
+instance ABIEncoding NoMethod where
+    fromDataParser = return NoMethod
+    toDataBuilder  = const ""
+
+instance Method NoMethod
diff --git a/src/Network/Ethereum/Web3/Encoding/Bytes.hs b/src/Network/Ethereum/Web3/Encoding/Bytes.hs
--- a/src/Network/Ethereum/Web3/Encoding/Bytes.hs
+++ b/src/Network/Ethereum/Web3/Encoding/Bytes.hs
@@ -25,8 +25,8 @@
 import Network.Ethereum.Web3.Encoding.Internal
 import Network.Ethereum.Web3.Encoding
 import GHC.TypeLits (KnownNat, Nat, natVal)
+import Data.Monoid (Monoid(..), (<>))
 import Data.ByteArray (Bytes)
-import Data.Monoid ((<>))
 
 import Debug.Trace
 
@@ -62,6 +62,10 @@
 -- | Dynamic length byte array
 newtype BytesD = BytesD { unBytesD :: Bytes }
   deriving (Eq, Ord)
+
+instance Monoid BytesD where
+    mempty = BytesD mempty
+    mappend (BytesD a) (BytesD b) = BytesD (mappend a b)
 
 instance EncodingType BytesD where
     typeName  = const "bytes[]"
diff --git a/web3.cabal b/web3.cabal
--- a/web3.cabal
+++ b/web3.cabal
@@ -1,5 +1,5 @@
 name: web3
-version: 0.5.1.0
+version: 0.5.2.0
 cabal-version: >=1.10
 build-type: Simple
 license: BSD3
@@ -64,7 +64,7 @@
         base >=4.9.0.0 && <4.10,
         memory ==0.13.*,
         text >=1.2.2.1 && <1.3,
-        web3 >=0.5.1.0 && <0.6
+        web3 >=0.5.2.0 && <0.6
     default-language: Haskell2010
     default-extensions: OverloadedStrings
     hs-source-dirs: test