diff --git a/lib/bufferwriter.js b/lib/bufferwriter.js
index 85a18fe..5bf5800 100644
--- a/lib/bufferwriter.js
+++ b/lib/bufferwriter.js
@@ -1,9 +1,17 @@
 var BN = require('./bn');
 
-var BufferWriter = function BufferWriter(bufs) {
+var BufferWriter = function BufferWriter(obj) {
   if (!(this instanceof BufferWriter))
-    return new BufferReader(buf);
-  this.bufs = bufs || [];
+    return new BufferReader(obj);
+  if (obj)
+    this.set(obj);
+  else
+    this.bufs = [];
+};
+
+BufferWriter.prototype.set = function(obj) {
+  this.bufs = obj.bufs || this.bufs || [];
+  return this;
 };
 
 BufferWriter.prototype.concat = function() {
diff --git a/test/test.bufferwriter.js b/test/test.bufferwriter.js
index 7ac33e5..acbc8f1 100644
--- a/test/test.bufferwriter.js
+++ b/test/test.bufferwriter.js
@@ -10,12 +10,24 @@ describe('BufferWriter', function() {
     should.exist(bw);
   });
 
+  describe('#set', function() {
+    
+    it('set bufs', function() {
+      var buf1 = new Buffer([0]);
+      var buf2 = new Buffer([1]);
+      var bufs = [buf1, buf2];
+      var bw = new BufferWriter().set({bufs: [buf1, buf2]});
+      bw.concat().toString('hex').should.equal('0001');
+    });
+
+  });
+
   describe('#concat', function() {
     
     it('should concat these two bufs', function() {
       var buf1 = new Buffer([0]);
       var buf2 = new Buffer([1]);
-      var bw = new BufferWriter([buf1, buf2]);
+      var bw = new BufferWriter({bufs: [buf1, buf2]});
       bw.concat().toString('hex').should.equal('0001');
     });