The RAP-B-404-238U consists of the medium Tough-Claw™ base, double socket arm and diamond base adapter. The RAM Tough-Claw™ is the perfect mounting base for quick and easy tool-less installation and removal on round, square, odd shaped rails and bars. The Tough-Claw™ can be clamped on rails from 1" to 1.875" outer diameter. The diamond base adapter contains the industry standard universal AMPS hole pattern, which will connect to a large variety of RAM Mount and third party cradles. The mount is designed with a RAM 1" diameter patented rubber ball and socket system that has adjustment points at both ends of the double socket arm; this allowing for almost infinite adjustment and perfect viewing angles. Clamping Range (Rail/Tube Surfaces):1" to 1.875"Clamping Range (Flat Surfaces):0" to 1.6"