The RAM Marine Grade Aluminum Yoke Mount consists of the 1" dia. ball and socket system with RAM Universal 2.5" diameter Plate. This mount is designed to be a universal mounting solution for both RAM and non-RAM designed products. The hole pattern found on the 2.5" Plate will connect to a large variety of third party cradles and mounts. The Yoke Clamp Mount Base fits a rail diameter from 5/8" to a maximum of 1 1/4". 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. To mount the base, simply place the yoke clamps around the rail and then screw the large knob at the end of the threaded rod. The hand tightened clamp makes this the perfect mounting system for rental planes and unusual shaped motorbike rails. The rail does not need to be perfectly round to mount this base.