"The RAM RAM-109VS-4U consists of a single swing arm mount with 1.5"" socket, 6"" long straight swing arm that is mounted on a vertical surface base. The connection between the swing arm and the base is a bolt pivot point. The open socket end will accept mounting bases with a RAM 1.5"" diameter ball, enabling a versatile RAM ball and socket system. The bolt pivoting point allows a complete 360 degree rotation and the ball and socket system allows a 180 degree vertical pivot with a 360 degree rotation."