RAM-B-121BU RAM YOKE CLAMP WITH 1 BALL
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.
Clamp Base Dimensions:
Accommodates rails from 0.625" to 1.25" in diameter