Look no further. Great item quality， that's solidly built. Best of all， its very affordable price. Buy without delay.<br />Material: aluminum<br />Inner diameter: 30-31.8mm<br />The accessory fixes Gopro to bike.<br />Suitable for all Hero & HD Hero 1 2 3 3+<br />1 x Bicycle mount<br /><img src="http://img6.eachbuyer.com/x9/p48/vt97_1.jpg" />                                                        <img src="http://img6.eachbuyer.com/x9/p48/vt97_2.jpg" />                                                        <img src="http://img6.eachbuyer.com/x9/p48/vt97_3.jpg" />                                                        <img src="http://img6.eachbuyer.com/x9/p48/vt97_4.jpg" />