Rokform [Galaxy S8] Pro-Series Adjustable Aluminum Bike Mount / Holder & Protective Phone Case, Twist Lock & Magnetic Security KEEPS YOUR PHONE SECURE: patented twist lock system & roksafe magnetic technology to keep your phone safe over even the roughest roads and trails ADJUSTABLE VIEWING ANGLE: Tilts from -20 to +55 degrees so you can view and access your phone while you ride. MILITARY GRADE: Constructed of durable 6061 T-6 aircraft grade aluminum with a stainless Steel screw to stand up to daily use and abuse-yet it's surprisingly lightweight QUALITY ALUMINUM CONSTRUCTION: designed and engineered to last USED by CHAMPION CYCLISTS: Used and endorsed by pros like Johnny OMara-a Motocross/Super cross Champion and master Cross Country Mountain Biking Champion