The RAM-B-149Z-GA23U consists of a double socket arm, zinc coated u-bolt base, diamond adapter base and custom high strength cradle for the Garmin nuvi 600 series. Designed into the mount is a 1" diameter patented rubber ball and socket system with adjustment points at the base and cradle. With a twist of the arm knob, you can move the motorcycle Garmin nuvi mount to your optimum viewing position. Included in this package is hardware that will accommodate rails from 0.50" to 1.25" in diameter.