The main body of the handlebar ball mount is made of 6061-T6 aluminum alloy material with CNC machining and iii grade hard anodized surface for durability and reliability in the most demanding environments. TPU over-molded ball head, non-slip and wear-resistant The round rail mount kit comes with three soft rubber ring inserts that provide a snug fit and protect the mounting surface. Three rubber ring diameters: 0.875" (22mm), 1" (25.4mm), 1.125" (28.6mm). The rubber ring can be increased or decreased according to the diameter of the round rails. The rail mount base have a 1.26" (32mm) diameter mounting hole when without the rubber ring insert The rail mount accommodates handlebars 0.875 inch (22mm) / 1 inch (25.4mm) / 1.125 inch (28.6mm) / 1.26 inch (32mm) in diameter. An Allen key is included with the package to facilitate your installation Compatible with RAM Mounts and BRCOVAN any B size 1 inch ball double socket arm. Work for other devices with 1 inch swivel ball mounting pattern. Great for motorcycle phone mounts, tablet mounts, navigation device mounts, action camera mounts, camcorder mounts, rod holders and much more in a wide variety of applications Ideal for mounting on the handlebars of bicycles, motorcycles, scooters, and other round rails of compatible sizes The Aluminum Alloy Handlebar Clamp Mount Base with 1'' TPU Ball for Rails 0.875'' / 1'' / 1.125'' / 1.26'' in Diameter, Compatible with RAM Mounts B Size Ball Double Socket Arm.