Powder coated marine grade aluminum mount. The round plate contains two mounting holes at 180° and three mounting holes at 120°. The rectangular plate contains a 4-hole pattern of 1.5" ? 4.5". The patented rubber ball and socket technology dampens shock and vibration, and allows for nearly infinite adjustability, So you can set your device at the perfect veiwing angle, while suited for any rugged environment. Weight capacity up to 15 lbs. Fits Humminbird Helix 9, Humminbird Helix 10, Humminbird Helix 12.