speed bag bladder

Replacement bladders come in Small, Medium, and Large. Small fits 7.5"-tall speed bags, Medium fits 9.5"-tall bags, and Large fits 10.5"-tall bags.

Replacement latex bladders include an exclusive valve design that locks in air and an extended stem that can be cut or trimmed to sit flush inside the bag.

Listings show several fill approaches: rubber fill, "No Fill" (the outer bag relies on an inner bladder), and inner bladders made of butyl rubber used in some professional bags.

The listings show three sizes with suggested skill levels: Small (7.5" x 5") for experts, Medium (9.5" x 6") for intermediate users, and Large (10.5" x 7") for beginners. (This reflects the listings' recommendations.)