This Five Oceans Inflatable Ribbed Black Boat Fender 4x16 inches is made of high-quality marine-grade UV-resistant PVC. It comes with ribbed on all sides for extra protection to enhance strength, increase friction, and resist abrasion for the boat. This Five Oceans Kit includes Four 4x16 inches Black Fenders, Four 3/8 in Fender Lines (5 feet long), and One Pump to inflate or deflate each fender to the desired pressure and 4 needles. Our Fender was designed with reinforced eyelets on both ends, it can be hung with lines vertically or horizontally. Valve seat is integrally molded into the fender, not glued-in like others.
A properly inflated fender will feel firm and still look cylindrical - no bulging sidewalls. In the absence of a pressure gauge, you should be able to depress the sidewall of the fender by about 1/2" with light finger pressure.