The RAM-B-121-202U consists of a yoke clamp base, standard length double socket arm and round 2.5" base that contains the universal AMPs hole pattern. The yoke clamp base will fit rails in diameter from 0.625" to a maximum of 1.25". The 1" rubber ball is at a right angle to the plane of the mount; when connected to a rail, the ball sits parallel to the rail. The mount is designed with a RAM 1" diameter patented rubber ball and socket system that has adjustment points at both ends of the double socket arm, allowing for almost infinite adjustment and perfect viewing angles.