RAM Mount RAM Double Socket Arm w/Round Ball Plate - C Size Long [RAM-103U-D]RAM Double Socket Arm with Round Ball Plate C Size Long The RAM 103U D consists of the 1. 5" C size diameter ball and socket system with one open socket end; the RAM 201U D socket arm is the long length at 9. 125" end to end with an 8" socket to socket length. This mount is designed to be used with any of the C size RAM Mount bases or cradles with a 1. 5" diameter rubber ball. The RAM 202U RAM Round Plate Ball Base features an industry standard AMPS