We offer 2 adustable sizes, small and large. This is the Large Version. See the sizing picture included and shop our store for your correct size. Durable High Quality Completely Weatherproof Patented Universal Clamp-on Mount Boat Cup Holders The large version universal clamp fits from 1 1/2 inch up to 2 inch outside diameter. Once installed, will rotate 360 when pushed around pipe but will not migrate down unless forced. Smart Cup - Fits, 20 & 30 oz. Larger Tumbler Cooler Cups & a can with or without a foam insulator. Stabilized to resist saltwater, UV damage, harsh outdoor elements & abuse. Comes w/slot for pliers. Will not get brittle, yellow, or break down.