The RAM-B-138-GA25LU consists of a 2.5″ diameter round base with the universal AMPS hole pattern, double socket arm, locking knob, diamond adapter base and custom high strength composite locking case. The locking case features the ability to secure your Garmin nuvi in place, adding much needed protection and enables full access to the screen, power plug, and memory card slot. The case consists of a front and back cover that can be secured together using standard pop rivets or security screws (not included.) The RAM cradle features a unique cable retention system that prevents accidental unplugging of the USB cable. 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 locking knob, you can move the Garmin nuvi flat surface mount to your optimum viewing position.