The RAP-B-299-4-UN8U consists of a spring loaded cradle with grip knobs on the back for a quick release function of your tablet. Connecting to the X-Grip is the RAM Stubby cup holder mount. The durable composite shell construction and flexible support fins can be trimmed to size make this cup holder base a portable and versatile solution. The RAM ball and socket system allows for articulation at both ends of the double socket arm creating almost infinite adjustment and perfect viewing angles. Compatible with any vehicle cup holder with an inside diameter range of 2.57" to 3.5".