The RAM-B-149Z-GA48 Garmin eTrex 10 20 30 Series Motorcycle RAM Mount is a Marine Grade Aluminum Mount with a Zinc Coated U-Bolt Rail Base and RAM Custom Plastic Cradle. The mount is designed with a RAM 1 inch diameter patented rubber ball and socket system that has adjustment point at the cradle and base. With a twist of the arm knob, you can move the Garmin eTrex 10 20 30 mount to your optimum viewing position.