These tubes are made of a heavy-duty, UV-resistant, 25-gauge Vinyl (PVC) material formulated to withstand long exposure in the sun, rock, sticks, and rough river conditions. With a 50-inch (deflated) outer diameter, 22-inch center diameter and the ergo’ backrest, these are the perfect size and height on the water to rest easy and comfortably for a long ride. Each tube comes with a large cup holder, 2 handles, mesh bottom, and a commercial Boston Air Valve for quick and easy inflation/deflation. Seams double welded to ensure no air leakage.