diff --git a/README.md b/README.md
index 79a8b81..b1713f5 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@ A convinience-wrapper arround protocol-buffers and lp-messages functions
 
 # API
 
-- `wrap(duplex)`: Wraps a duplex, returns below object
+- `wrap(duplex, opts)`: Wraps a duplex, returns below object (opts=Object with .lengthEncoder, .lengthDecoder from [it-length-prefixed api](https://www.npmjs.com/package/it-length-prefixed#api))
   - `.read(bytes)`: async, reads the given amount of bytes
   - `.readLP()`: async, reads one length-prefixed message
   - `.readPB(proto)`: async, reads one protocol-buffers length-prefixed message (proto=Object with .encode, .decode functions)
diff --git a/src/index.js b/src/index.js
index a255aed..4e50cc1 100644
--- a/src/index.js
+++ b/src/index.js
@@ -3,9 +3,9 @@
 const Shake = require('it-handshake')
 const lp = require('it-length-prefixed')
 
-module.exports = (duplex) => {
+module.exports = (duplex, opts = {}) => {
   const shake = Shake(duplex)
-  const lpReader = lp.decode.fromReader(shake.reader)
+  const lpReader = lp.decode.fromReader(shake.reader, { lengthDecoder: opts.lengthDecoder })
 
   let isDone = false
 
@@ -24,7 +24,7 @@ module.exports = (duplex) => {
       if (!value) { throw new Error('Value is null') }
       return value
     },
-    readLP: async (useBE32) => {
+    readLP: async () => {
       // read, decode
       const { value, done } = await lpReader.next()
 
@@ -46,9 +46,9 @@ module.exports = (duplex) => {
       // just write
       shake.writer.push(data)
     },
-    writeLP: (data, useBE32) => {
+    writeLP: (data) => {
       // encode, write
-      W.write(lp.encode.single(data))
+      W.write(lp.encode.single(data, { lengthEncoder: opts.lengthEncoder }))
     },
     writePB: (data, proto) => {
       // encode, writeLP
diff --git a/test/index.js b/test/index.js
index 3194f8a..82c871e 100644
--- a/test/index.js
+++ b/test/index.js
@@ -4,6 +4,7 @@ const Pair = require('it-pair')
 const { collect } = require('streaming-iterables')
 const Wrap = require('..')
 const assert = require('assert').strict
+const { int32BEDecode, int32BEEncode } = require('it-length-prefixed')
 
 /* eslint-env mocha */
 /* eslint-disable require-await */
@@ -26,12 +27,30 @@ describe('it-pb-rpc', () => {
       assert.deepEqual(data, res.slice())
     })
 
-    it.skip('lp fixed', async () => {
+    it('lp fixed encode', async () => {
+      const duplex = Pair()
+      const wrap = Wrap(duplex, { lengthEncoder: int32BEEncode })
       const data = Buffer.from('hellllllllloooo')
 
-      w.writeLP(data, true)
-      const res = await w.readLP(true)
-      assert.deepEqual(data, res.slice())
+      wrap.writeLP(data)
+      const res = await wrap.read()
+      const length = Buffer.allocUnsafe(4)
+      length.writeInt32BE(data.length, 0)
+      const expected = Buffer.concat([length, data])
+      assert.deepEqual(res.slice(), expected)
+    })
+
+    it('lp fixed decode', async () => {
+      const duplex = Pair()
+      const wrap = Wrap(duplex, { lengthDecoder: int32BEDecode })
+      const data = Buffer.from('hellllllllloooo')
+      const length = Buffer.allocUnsafe(4)
+      length.writeInt32BE(data.length, 0)
+      const encoded = Buffer.concat([length, data])
+
+      wrap.write(encoded)
+      const res = await wrap.readLP()
+      assert.deepEqual(res.slice(), data)
     })
   })