The Pier Cushion is larger and more durable than any other fender or cushion on the market. Each cushion has over 5 lbs. of material in it.The convex back allows the pier cushion to contour to posts better than other boat cushions. The Pier Cushion is easy to apply and will fit up to a 9" diameter round or square post and can fit vertically or horizontally. This cushion is inflatable and made of UV resistant all PVC construction, 23" long, 7" wide and 4 1/2" deep. The vinyl strap cushion is portable but may also be made permanent by screwing the straps to the post. Air may be added after The Pier Cushion is secured. Remember to fasten the straps tightly. It is not necessary to use air pressure. Do not over fill and cause The Pier Cushion to lose it"s shape. A small amount of air volume is all that is necessary. When you apply The Pier Cushion to a post it becomes much firmer. The Pier Cushion will expand and contract based on the air temperature. Any ordinary basketball needle may be used to inflate The Pier Cushion. Proudly made in the USA!