This GoPro Roll Bar Mount for GoPro Hero 1, Hero 2, Hero 3, Hero 3 / Hero 3 Plus and Hero 4 Camera - Black fits 1.4" to 2.5" (3.5cm - 6.35cm) diameter tubes. This GoPro Roll Bar Mount for GoPro Hero 1, Hero 2, Hero 3, Hero 3 / Hero 3 Plus and Hero 4 Camera - Black is perfect for clamping your camera to the radiator cap (both metal and plastic caps) on karts. You can also clamp to bike frames, bumper bars, ski/surfboard racks, or anything else that is in the size range above. Used with pivoting orientation arms allowing for 3-way adjustability, ensuring you can get the angle you want.