The RAM-B-166-GA48 consists of a double socket arm, 3.3" twist lock suction cup base, diamond adapter base and custom high strength composite cradle for the Garmin eTrex 10, 20 and 30. The suction cup, twist lock base is designed to have a strong hold on glass and non-porous plastic surfaces, including adhesive disks. 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 suction cup eTrex mount to your optimum viewing position.