RAM C Size 1.5" Ball Mount with 2/2.5" Round Plate AMPs Hole PatternThe RAM-101U consists of a double socket arm and two 2.5" diameter round bases that contain the universal AMPS hole pattern. The mount is designed with a 1.5" diameter patented rubber ball and socket system that has adjustment points at both ends of the double socket arm; this allowing for almost infinite adjustment and perfect viewing angles. The hole pattern found on the round base adapter will connect to many RAM cradles, including all iPad cradles. The included RAM’s patented design dampens shock and vibration, helping to extend the life of your device.