This 1'' ball handlebar clamp mount base accommodates handlebars 0.5 inch (12mm) / 0.87 inch (22mm) / 1 inch (25.4mm) / 1.125 inch (28.6mm) / 1.26 inch (32mm) in diameter Package come with four soft rubber ring inserts to provide a snug fit and protection of the mounting surface. Rubber ring inserts diameter: 0.5''(12mm), 0.87''(22mm), 1''(25.4mm), 1.125''(28.6mm). You can add or remove rubber ring according to the diameter of handlebar. When the rubber ring insert is not embedded, the hole diameter of the handlebar mounting base is 1.26" (32mm) The handlebar ball mount utilizes rubber-insert and lock-bolt to prevent loosening in high vibration for mounting to motorcycle & bike handlebars and rear-view mirror as well as other round rails within the stated dimensions. An Allen key is included with the package to facilitate your installation Main body made of 6061-T6 aluminum alloy for durability and reliability in the most demanding environments. CNC integral molding, solid structure. Anodized surface treatment, smooth surface, durable. TPU over-molded ball head, non-slip and wear-resistant. This 1 inch ball handlebar mounting base compatible with RAM Mounts & BRCOVAN any B size 1'' ball double socket arms. Work for other devices with 1 inch swivel ball mounting pattern. The aluminum alloy handlebar clamp mount with 1'' TPU ball for round rails diameter 0.5'' 0.87'' 1'' 1.26'', compatible with RAM Mounts B size 1 Inch ball double socket arm. Main body made of 6061-T6 aluminum alloy for durability and reliability in the most demanding environments. CNC integrated molding, smooth surface and solid body. TPU over-molding ball head, with anti-slip performance.