Made of high-strength composite and stainless steel hardware for durability and reliability. Spring-loaded 'X' design for large phones with rubber caps; includes optional device tether. Low-profile mount clamps to your handlebar with the turn of a single knob. With Tough-Claw™ base connected, easily attached the X-Grip® on round, square and odd shaped rails and bars. Rubber pads provide stable gripping and protection of mounting surface. Clamp range: 0.625" to 1.5" diameter, 0" to 1.14" on flat surfaces. Small phone mount dimensions: 1.875" to 3.25" W, 0.875" D. Large phone mount dimensions: 1.75" to 4.5" W, 0.875" D.