Boatmates Marine Drink Holder with Koozie Handy, compact drink holder has a suction cup that can be placed on the back or on the bottom, to keep your favorite beverage in place on any smooth, flat surface. Get one for every member of the crew! The Super Suction cups stay securely fastened, even in the roughest conditions. Can also be permanently mounted with screws. Measures 3-1/2 dia. x 3-1/4H.