The RAM-B-166-GA32 consists of a 3.25" twist lock suction cup base, standard length double socket arm, diamond adapter base and high strength composite cradle for the Garmin nuvi. The suction cup, twist lock base is designed to have a strong hold on glass and non-porous plastic surfaces, including RAM adhesive disks. 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 you to move the mount to your optimum viewing position. Compatible Devices Garmin nuvi 220, Garmin nuvi 500, Garmin nuvi 510, Garmin nuvi 550, Garmin zumo 220.