This 1'' ball 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. Tool-less design for easy installation or removal 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 The 1'' ball mount 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, anti-slip and wear-resistant This 1 inch ball handlebar mount 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 Mount with 1'' TPU Ball for Rails Diameter 0.5'' 0.87'' 1'' 1.125'' 1.26'', Compatible with RAM Mounts B Size 1 Inch Ball Double Socket Arm, Tool-less design for easy installation or removal. 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. (Set of 5)