Aluminum alloy， diameter 44mm  <br />For mountain bike， road bike. <br />Cycling essentials for road bike lovers.<br />Color: Black <br />Material: Metal <br />Overall Size: about 50 x 50 x 44 mm <br />Inner diameter: about 28.9mm <br />Thread diameter: about 5.62mm<br />1 x Threadless Headset<br /><img src="http://img6.eachbuyer.com/x21/p38/bq664_1.jpg" />                                                        <img src="http://img6.eachbuyer.com/x21/p38/bq664_2.jpg" />                                                        <img src="http://img6.eachbuyer.com/x21/p38/bq664_3.jpg" />                                                        <img src="http://img6.eachbuyer.com/x21/p38/bq664_4.jpg" />                                                        <img src="http://img6.eachbuyer.com/x21/p38/bq664_5.jpg" />