This UltimateAddons handlebar mounting attachment can be used with any of UltimateAddons 3 prong device holders and cases. This quick release attachment allows you to quickly and easily remove your holder/case form your vehicle while leaving the attachment connected. The UltimateAddons quick release attachment can be fitted to vehicles handlebars / frame with a diameter between approx. 21mm - 30mm. The mounting attachment has a rubber grip inside to help with securing it. There is an easy-twist screw to tighten the attachment to the required size.