The RAM Quick-Grip™ with Ratcheting Twist-Lock™ Suction Cup consists of a 3.3" diameter suction base ratchet adjustment composite single socket arm and spring loaded cradle for supporting most phones. The Twist-Lock™ Suction Cup is designed to have a strong hold on any windshield glass and non-porous surface. The ratchet adjustment in conjunction with the swiveling single socket arm allows you to set your phone to the optimal viewing position.