Boat cup holder made of Made of ABS plastic, The cup holder clip with anti- rubbers the grip is strong , mount to rail, adjustable knob willl make the cup holder rock solid on the rail, you can put drinks in these cup holders and not worry about them spilling all over . Boat rail cup holder can hold water bottles, coffee cups, beer, cans, glas and so on.Mounts to rails on boat, Can move cup holders to any rail.Suitable for Yacht, Pontoon boat, bass boat, Jon boat, Kayak and so on. The cup holders are easy to install, just clamp and go without any tools and assemblies,no drilling needed and no damage to boat,mount on boat aluminum rail, pole or bimini top rail. Boat drink holder is simple, unique, durable and practical as well, designed cup holder can hold different size bottles.adjustable clamp allows rotation , And with horizontal poles or any slanted poles, not just vertical.so it can be installed on different angle.with anti- rubbers keep the bottle fixed inside , prevent drinks from spilling and falling downPontoon Boat, Bass Boat, Jon Boat, Jet Ski . Universal Drinks Holders are space inside can hold miscellaneous items. Suntan lotion, fish pliers, drinks, hand wipes, lures, Some little rubbish and so on.