RAM MOUNTS' RAM-B-103U 2.5 in round base and double socket arm that will accept 1 in ball bases. The round base contains pre-drilled holes, including the universal AMPS hole pattern. Designed into the mount is a 1 in 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.