SeaLux Stainless Steel Adjustable Fold Down cup, drink and Mug Holder for boat, car 3" or 3-3/4" opening (3-3/4" Mug Holder (Large)) SeaLux SS Adjustable Fold Down Mug, Cup Drink Holder (Large, Max. opening 3-3/4") Fabricated from 304 stainless steel, Corrosion resistance. Highly mirror polished finish and elegant aesthetically design The space saving folding design is also equipped with molded silicone retainer arms to adjust to varying size of cans, cups, cozies and mugs. The ultimate in function, style and space efficiency. Ideal product for automobile, watercraft, RV. Easy installation, could be mount on any flat vertical surface. Adjustable Retainer Arms opening from 1" to 3-3/4" diameter. (Large size)