RAM Mount Yoke Clamp Mount w/Double Socket Arm & Round Base [RAM-B-121-202U]RAM Yoke Clamp Mount with Double Socket Arm and Round Base Adapter The RAM B 121 202U consists of a double socket arm, round 2. 5" base that contains the universal AMPs hole pattern and yoke clamp base. The clamp base will accommodate rails in diameter from 0. 625" to 1. 25". The 1" rubber ball is at a right angle to the plane of the mount so when connected to a rail, the ball sits parallel to the rail. This mount is designed to be a universal