The Replacement Bladder for W10521 can help you repair your volleyball. It is made for the 36" ultralight volleyball. You will be able to enjoy hours of fun practice after installing it. Crafted with durability in mind, the volleyball bladder will hold up to continuous use. You can play with peace of mind that your ball will stay intact. Enjoy a lightweight and comfortable feel. This is an ideal addition to almost any volleyball player's equipment.