The RAP-299-3U serves as a mounting point for RAM 1" double socket ball mounts. Insert the mount into any cupholder ranging from 2.57" to 3.5"in diameter. KEY FEATURES Fits cup holders between 2.57" - 3.5" inside diameter 2-Hole AMPS: 1.912" Overall Height: 4.75" High strength composite Comes with two (2) #10 x 3/4" Sheet Metal Screws Included are support fins that flex, making the cup holder base conform to most vehicle cup holders. Also included is hardware to attach a AMPS 2-Hole (Diamond) base to the cup holder base. Compatible with any vehicle cup holder with an inside diameter range of 2.57" to 3.5".