RAM 11mm Bolt Head Adapter Base w/ 1" Ball and is secured firmly using

and is secured firmly using one screw (supplied) on each side

You can also mount a GoPro Karma Grip onto the 3-prong mount by using the Mounting Ring that comes with the Karma Grip

either flat or curved type

This filter kit includes a circular polarizer

RAM Mounting Systems and GoPro® make it possible to truly "Be a HERO™"

RAM 11mm Bolt Head Adapter Base w/ 1" Ball and is secured firmly usingThe RAM B 252U marine grade aluminum base consists of a 1" diameter ball and 2. 25" x 0. 875" base with 11mm hole. This part is often used on motorcycles, attaching to the mirror frame, the main brand of bike for the RAM B 252U is BMW. This part fits well on many handlebar pinchbolts with a washer (base is 5mm thick).