Marine Grade Stainless Single Ring Cup Drink Holder - open design - with Screw Single Stainless Drink Holder with screw is cast from solid marine-grade 316 stainless. Single drink holders are designed to fit Koozies, cans, mugs and large cups up to 3-3/8” in diameter. The elegant design also features an open frame to accommodate coffee cup handles. The drink holders sit 3” high when installed and are highly polished. A locator stud keeps them from turning. A rubber seal is included to seal he water and protection for the boat