Small version of the RAM Tough-Claw base is designed to quickly clamp to round, square, and odd-shaped rails and bars ranging from .625" to 1.5" in outer diameter; rubber pads provide stable gripping and protection of mounting surface Spring-loaded 'X' design with rubber caps sports great holding power without hiding your phone; includes optional device tether for peace of mind during rugged use Made of high-strength composite and stainless steel hardware for durability and reliability in the most demanding environments Holder dimensions: Width Range: 1.875" - 3.25"; Depth Range: 0.875" max Rail/Tube Clamp Range: 0.625" - 1.5" Diameter; Flat Surface Clamp Range: 0" - 1.14" Backed by a lifetime warranty The RAM Tough-Claw is the perfect mounting base for toolless installation and removal on round, square, and odd-shaped rails and bars. The small version of the RAM Tough-Claw includes a B size 1" rubber ball and can quickly be clamped on rails ranging from 1.87" to 3.25" in outer diameter – ideal for mounting mounting on the yoke of an aircraft, handlebars of bicycles and motorcycles, or even on kayak rails and roll bars. This kit includes a medium length double socket arm and the popular spring-loaded RAM X-Grip phone holder, featuring an 'X' design that expands and contracts to provide a perfect fit for your device – even if it's in a case. The standard size version of the RAM X-Grip fits phones ranging from 1.75" to 4.5" in width and keeps your device completely functional and accessible. For outdoor applications, the RAM X-Grip includes a device tether that is recommended for added security and peace of mind.