The RAP-299-3-B-102U is a versatile mount that allows you to attach a variety of different devices. The universal base fits into a cup holder, so you don't have to do any drilling into a dash, or worry about a suction cup not holding. It comes with a double socket extension that can be adjusted at both ends and will work with the RAM X-Grips for cell phones or tablets or you can attach a device that uses the standardized AMPS mounting system such as a satellite radio or GPS. The diamond bases measure 2.43" x 1.31" diamond base and contain two holes 1.912" from center to center, positioned at both ends of the diamond base and use a 1" Rubber Ball.