The RoadVise Clamp Mount with 20mm ball is designed for wide-range clamping. The heavy-duty mount is made of high-strength composite materials with corrosion-resistant stainless-steel hardware. The clamp mount opens to 2.75” diameter to securely grip roll bars, tubes, handlebars, warehouse carts, etc. The 20mm ball (0.78”) is compatible with 20mm (0.78”) shafts.