The RAM-HOL-UN8B consists of a spring loaded cradle and 1" rubber ball connected to the back of the base. Included are extra easy access grip knobs, located on the back of the cradle for quick release of your tablet. The RAM-HOL-UN8B expands and contracts for perfect fit of most 7"-8" (17,8cm to 20,3cm) tablets. The X-Grip® includes a device tether recommended for outdoor applications. The cradle is compatible with handheld devices that will fit the dimensions listed below. It is important to verify the dimensions of your handheld device with a case/sleeve/skin when determining the overall size.