RAM 1" Diameter Ball Double Socket Arm with 2.5" Round Base that contains the AMPs Hole PatternPart #: RAM-B-103UThe RAM-B-103U consists of a 2.5" round base and double socket arm that will accept 1" ball bases. The round base contains pre-drilled holes, including the universal AMPS hole pattern. Designed into the mount is a 1" diameter patented rubber ball and socket system with adjustment points at both ends of the socket arm; this with a twist of the arm knob allows for you to maneuver the mount to your optimum viewing position. Material: Powder Coated Marine Grade Aluminum Ball Size: 1" Rubber "B" Ball Size Note: The "U" in the part number reflects product packaged in poly bag. | RAM Mount Double Socket Arm w/ 2.5" Round Base