Extra durable, tough and resilient butyl rubber replacement bladders Built for super speed, precision rebounds and professional training Always keep a spare around for emergencies Color may vary Available in multiple sizes to fit any speed bag Extra durable, tough and resilient butyl rubber replacement bladders are specifically manufactured for every speed bag we offer. Built for super speed, precision rebounds and professional training. Always keep a spare around for emergencies! XS fits sizes: 4” x 6”, 4” x 7” speed bags, S fits sizes: 5” x 7”, 5" x 8" speed bags, M fits sizes: 6" x 9", 7" x 10" speed bags, and L fits sizes: 8" x 11", 10" x 12" speed bags. Color may vary.