Ultimate Addons 15mm Motorcycle Bike Fork Stem Yoke Mount with Dedicated Cradle for Apple iPhone 4S (sku 13367) The central fork stem yoke mount has been developed for use on motorcycles where a handlebar mounting option is not possible or desirable. 15mm - Fits Fork Stems 15mm - 17mm (0.59" - 0.68") Designed to fit sports, superbike, endurance and touring motorbikes using the cylindrical bore wall (steering head tube) of the fork stems. 1" Ball fixing to connect mount to case. Light weight - made from Aluminium. Attaches easily to the steering head tube of fork stems. First check that the stem cover can be removed leaving a central hole for the mount to fix in. Simply drop the Fork Stem Motorcycle attachment into the hole of the stem and tighten. The split shaft will expand to fit the inside wall of the fork stem. Use an Allen Key to tighten to create a tight fit. Dedicated iPhone 4s cradle Moulded design with secure retaining lip. Video / camera lens clearance Cradle can be swivelled 360 degrees allowing you to view horizontally or vertically, ideal for satnav apps.