RAM X-Grip Phone Mount with Drill-Down Base (RAM-B-138-UN7U) (sku 50909)RAM X Grip Phone Mount with Drill Down Base (RAM B 138 UN7U) The RAM B 138 UN7U consists of a 2. 5" diameter round base with the universal AMPS hole pattern, double socket arm and universal spring loaded X Grip cradle for cell phones. Designed into the mount is a 1" diameter patented rubber ball and socket system with adjustment points at the both ends of the socket arm; this with a twist of the arm knob, allows you to move the mount to your optimum