diff --git a/deno.json b/deno.json
index 85ae88c..3ba8c05 100644
--- a/deno.json
+++ b/deno.json
@@ -1,6 +1,6 @@
 {
   "name": "@tls/keyexchange",
-  "version": "0.0.9",
+  "version": "0.1.0",
   "exports": "./src/mod.ts",
   "publish": {
     "exclude": ["dist/"]
diff --git a/src/clienthello.js b/src/clienthello.js
index 2b376d3..7d2126f 100644
--- a/src/clienthello.js
+++ b/src/clienthello.js
@@ -20,7 +20,7 @@ export class ClientHello extends Struct {
    cipher_suites; // offset = 33;
    legacy_compression_methods; // offset = 33 + cipher_suites.length
    extensions;
-   ext = {};
+   ext = new Map;
    static fromHandShake(handshake) {
       const copy = Uint8Array.from(handshake);
       let offset = 0;
@@ -65,9 +65,12 @@ export class ClientHello extends Struct {
       this.legacy_session = legacy_session;
       this.cipher_suites = cipher_suites;
       this.legacy_compression_methods = legacy_compression_methods
+      let offset = legacy_version.length + random.length + legacy_session.length
+         + cipher_suites.length + legacy_compression_methods.length;
       this.extensions = extensions;
       for (const ex of extensions) {
-         this.ext[ex.extension_type?.name] = ex.extension_data
+         this.ext.set(ex.extension_type?.name, {pos: offset + 2, data: ex.extension_data});
+         offset += ex.length;
       }
    }
    static fromServerName(serverName) {
@@ -85,12 +88,17 @@ export class ClientHello extends Struct {
          ))
       )
    }
-   toRecord() { 
+   toRecord() {
       return ContentType.HANDSHAKE.tlsPlainText(
          HandshakeType.CLIENT_HELLO.handshake(this)
-      ) }
-   add(data){ 
-      const array = safeuint8array(this, data);
+      )
+   }
+   addBinders(binders) {
+      const psk = this.ext.get('PRE_SHARED_KEY');
+      const lengthOf = psk.data.length + binders.length;
+      const uint16 = Uint16.fromValue(lengthOf)
+      const array = safeuint8array(this, binders);
+      array.set(uint16, psk.pos + 2); 
       return ClientHello.from(array)
    }
 }
diff --git a/src/serverhello.js b/src/serverhello.js
index 1f2fe2b..023e464 100644
--- a/src/serverhello.js
+++ b/src/serverhello.js
@@ -101,8 +101,8 @@ function parseExtension(extension) {
 function fromClient_hello(clientHello) {
    const { legacy_session, cipher_suites, ext } = clientHello;
    const { ciphers } = cipher_suites;
-   const { KEY_SHARE } = ext;
-   const { keyShareEntries } = KEY_SHARE
+   const KEY_SHARE = ext.get('KEY_SHARE');
+   const { keyShareEntries } = KEY_SHARE.data;
    const cipherPreferences = new Set([Cipher.AES_128_GCM_SHA256, Cipher.AES_256_GCM_SHA384, Cipher.CHACHA20_POLY1305_SHA256]);
    const namedGroupPreferences = new Set([NamedGroup.X25519, NamedGroup.SECP256R1, NamedGroup.SECP384R1])
    const cipher = cipherPreferences.intersection(ciphers).values().next().value//selectFirstMatch(ciphers, cipherPreferences);
diff --git a/test/clienthello_test.js b/test/clienthello_test.js
index cd2b949..336e0c8 100644
--- a/test/clienthello_test.js
+++ b/test/clienthello_test.js
@@ -89,5 +89,9 @@ const clientHelloPSKBinder = HexaDecimal.fromString(
 ).byte
 
 const clientHelloPSKBinderBack = ClientHello.fromHandShake(clientHelloPSKBinder);
+const binders = HexaDecimal.fromString(`00 21 20 3a dd 4f b2 d8 fd f8 22 a0 ca
+         3c f7 67 8e f5 e8 8d ae 99 01 41 c5 92 4d 57 bb 6f a3 1b 9e 5f
+         9d`).byte;
+const clientHelloPsk_0 = clientHelloPSKBinderBack.addBinders(binders)
 
 debugger;
\ No newline at end of file
diff --git a/type/clienthello.d.ts b/type/clienthello.d.ts
index 3622eba..49ad0c4 100644
--- a/type/clienthello.d.ts
+++ b/type/clienthello.d.ts
@@ -81,10 +81,10 @@ export class ClientHello extends Struct {
   /**
    * Appends the given data to the current instance and creates a new `ClientHello` object.
    *
-   * @param {Uint8Array} data - The data to be appended. Must be a valid `Uint8Array`.
+   * @param {Uint8Array} binders - The data to be appended. Must be a valid `Uint8Array`.
    * @returns {ClientHello} A new `ClientHello` instance with the combined data.
    */
-  add(data: Uint8Array): ClientHello;
+  addBinders(binders: Uint8Array): ClientHello;
 }
 
 /**