Textured ABS Plastic 2 Jumbo Cup Drink holder 1-1/4 Rail. PLEASE Look at last 2 pictures so you know your rail size If you have a pontoon boat you will LOVE this. Mounts on any pontoon boat with a 1 1/4 inch pontoon rail or square tubing. Great for newer pontoon boats with the larger rails and holds a Large 30 oz drink. It's strong too. Made with 3 /16 Thick Textured ABS PLASTIC so it won't Crack-Chip-Fade-rust, could last you forever. To mount this just remove cup, slide over railing, reinstall the plastic cups that's it. Best part is, it can still slide on the rail but can't fall off. So you can put it anywhere on the boat. If you go swimming you can turn it so you can hold your drink outside the boat too. Please note : also available in Diamond plate and Other cup sizes check sellers other items for more options. ABS plastic tends to have a couple of scratches on the underside of the holder. Once installed you do not see them.