diff --git a/lib/bcoin/coin.js b/lib/bcoin/coin.js
index 27273ad2..e7188b91 100644
--- a/lib/bcoin/coin.js
+++ b/lib/bcoin/coin.js
@@ -32,8 +32,6 @@ function Coin(tx, index) {
     this.height = tx.height;
     this.value = tx.outputs[index].value;
     this.script = tx.outputs[index].script;
-    this._offset = tx.outputs[index]._offset;
-    this._size = tx.outputs[index]._size;
     this.coinbase = tx.isCoinbase();
     this.hash = tx.hash('hex');
     this.index = index;
@@ -47,8 +45,6 @@ function Coin(tx, index) {
     this.coinbase = options.coinbase;
     this.hash = options.hash;
     this.index = options.index;
-    this._size = options._size || 0;
-    this._offset = options._offset || 0;
   }
 
   if (Buffer.isBuffer(this.hash))
@@ -75,10 +71,6 @@ Coin.prototype.getSize = function getSize() {
   return 4 + 4 + 8 + this.script.getSize() + 32 + 4 + 1;
 };
 
-Coin.prototype.isCoinbase = function isCoinbase() {
-  return false;
-};
-
 Coin.prototype.getConfirmations = function getConfirmations(height) {
   var top;
 
diff --git a/lib/bcoin/input.js b/lib/bcoin/input.js
index d902ae09..5ebad7ef 100644
--- a/lib/bcoin/input.js
+++ b/lib/bcoin/input.js
@@ -7,6 +7,8 @@
 var bcoin = require('../bcoin');
 var utils = require('./utils');
 var assert = utils.assert;
+var BufferReader = require('./reader');
+var BufferWriter = require('./writer');
 
 /**
  * Input
@@ -22,8 +24,6 @@ function Input(options, tx) {
   this.script = options.script || new bcoin.script([]);
   this.sequence = options.sequence == null ? 0xffffffff : options.sequence;
   this.witness = options.witness || new bcoin.script.witness([]);
-  this._size = options._size || 0;
-  this._offset = options._offset || 0;
   this._witnessSize = options._witnessSize || 0;
   this._witnessOffset = options._witnessOffset || 0;
   this._mutable = !tx || (tx instanceof bcoin.mtx);
@@ -270,13 +270,13 @@ Input.fromRaw = function fromRaw(data, enc) {
 };
 
 Input.prototype.toExtended = function toExtended(enc) {
-  var input = bcoin.protocol.framer.input(this);
-  var witness = this.witness.encode();
-  var data = new Buffer(data.length + witness.length);
-  var off = 0;
+  var p = new BufferWriter();
+  var data;
 
-  off += utils.copy(input, data, off);
-  off += utils.copy(witness, data, off);
+  bcoin.protocol.framer.input(this, p);
+  bcoin.protocol.framer.witness(this.witness, p);
+
+  data = p.render();
 
   if (enc === 'hex')
     data = utils.toHex(data);
@@ -285,13 +285,16 @@ Input.prototype.toExtended = function toExtended(enc) {
 };
 
 Input._fromExtended = function _fromExtended(data, enc) {
-  var input;
+  var input, p;
 
   if (enc === 'hex')
     data = new Buffer(data, 'hex');
 
-  input = bcoin.protocol.parser.parseInput(data);
-  input.witness = bcoin.protocol.parser.parseWitness(data.slice(input._size));
+  p = new BufferReader(data);
+  p.start();
+  input = bcoin.protocol.parser.parseInput(p);
+  input.witness = bcoin.protocol.parser.parseWitness(p).witness;
+  p.end();
 
   return input;
 };
diff --git a/lib/bcoin/mempool.js b/lib/bcoin/mempool.js
index 0e9d06e2..cd5ed45f 100644
--- a/lib/bcoin/mempool.js
+++ b/lib/bcoin/mempool.js
@@ -291,7 +291,7 @@ Mempool.prototype.addTX = function addTX(tx, peer, callback, force) {
         self.verify(tx, function(err) {
           if (err) {
             if (err.type === 'VerifyError') {
-              if (err.score > -1)
+              if (err.score !== -1)
                 peer.sendReject(tx, err.reason, err.score);
               return callback(err);
             }
@@ -356,7 +356,7 @@ Mempool.prototype.verify = function verify(tx, callback) {
     input = tx.inputs[i];
     coin = input.output;
 
-    if (coin.isCoinbase()) {
+    if (coin.coinbase) {
       if (this.chain.height - coin.height < constants.tx.coinbaseMaturity)
         return callback(new VerifyError('bad-txns-premature-spend-of-coinbase', 0));
     }
diff --git a/lib/bcoin/mtx.js b/lib/bcoin/mtx.js
index aefc05fd..52b667c6 100644
--- a/lib/bcoin/mtx.js
+++ b/lib/bcoin/mtx.js
@@ -41,7 +41,6 @@ function MTX(options) {
   this._whash = null;
   this._raw = null;
   this._size = 0;
-  this._offset = 0;
   this._witnessSize = 0;
 
   this.height = -1;
diff --git a/lib/bcoin/output.js b/lib/bcoin/output.js
index f3a9cd85..5e038df3 100644
--- a/lib/bcoin/output.js
+++ b/lib/bcoin/output.js
@@ -30,8 +30,6 @@ function Output(options, tx) {
 
   this.value = utils.satoshi(value || new bn(0));
   this.script = options.script || new bcoin.script([]);
-  this._size = options._size || 0;
-  this._offset = options._offset || 0;
   this._mutable = !tx || (tx instanceof bcoin.mtx);
 
   // For safety: do not allow usage of
diff --git a/lib/bcoin/tx.js b/lib/bcoin/tx.js
index 4c8207d5..edeec60f 100644
--- a/lib/bcoin/tx.js
+++ b/lib/bcoin/tx.js
@@ -40,7 +40,6 @@ function TX(data, block, index) {
   this._whash = null;
   this._raw = data._raw || null;
   this._size = data._size || 0;
-  this._offset = data._offset || 0;
   this._witnessSize = data._witnessSize || 0;
 
   this.height = data.height != null ? data.height : -1;