The RAP-B-400-GOP1U consists of the small Tough-Claw base, double socket arm and B size 1" diameter ball with custom GoPro/Action Camera 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 0.625" - 1.5" outer diameter. The GoPro/Action Camera adapter attaches directly to the under-side of the camera, replacing the factory mounting bracket. Clamping Range (Rail/Tube Surfaces): 0.625" to 1.5" Clamping Range (Flat Surfaces): 0" to 1.14"