EXTENDABLE BASE: Insert is expandable from 2.6"-3.8" in diameter to fit many different automotive cupholders. Just twist the top of the adapter to expand or retract the base. It also works great for golf-carts, motorcycles, boats, trucks, and RV's. Our extra thick pads on the expanding base ensure the adapter stays securely in your cup holder. | RUBBER TABS SECURELY HOLD 2.8"-3.85" DIAMETER BOTTLES: The tabs are made from a proprietary material selected to make it easy to insert and remove bottles from the adapter. This ensures the adapter will not come out of your car’s cup holder when you remove the bottle to take a drink. | EXTENDER DESIGNED FOR ALMOST ANY SIZE BOTTLES: The multi-length rubber tabs allow the adapter to work with bottles/cups 2.8"-3.85" in diameter and fits most 20oz. - 40 oz. water bottles. Slot on side allows mugs with handles to fit. | BOTTOM (BASE) CAN BE OFFSET WITH A SINGLE ADJUSTMENT BOLT: The adapter can then be positioned so that it will not block the adjacent cup holder, two adapters can be used side by side, and the adapter can still work where a center console lid, emergency brake, dash, or lid covering the car’s cup holders would normally prevent the adapter from fitting properly. | ONE YEAR WARRANTY: The adapter is designed to handle even the most rugged driving conditions. We stand behind our product 100%.