RAM Mounts U-Bolt Short Arm GoPro Kit Features Consists of a zinc coated u-bolt base, short size double socket arm and 1 diameter ball with custom GoPro Hero adapter with a 2.38 mount arm Designed with a RAM 1 diameter patented rubber ball and socket system that has adjustment points at both ends of the double socket arm this allowing for almost infinite adjustment and perfect viewing angles Hardware included that will accommodate rails from 0.50 to 1.25 in diameter The base includes black cover caps to be placed over the exposed ends of the u-bolt. Included composite rail adapter can narrow the rail to a minimum width of 0.5