Because you've got more important things to do than watch a cage ball grow or shrink in size. Extra-large valve allows fast inflation/deflation so you save time in prep, put-away, and play. New, uncompromising double-welded vinyl bladders are also the heaviest, most durable we offer. Heavyweight nylon cover is double-stitched and sports an exclusive, extra-wide zippered opening under protective padding for effortless bladder insertion/removal. Cage balls include cover and bladder.