Ordinary heavy punchbags have a tendency to get compressed with use by boxers so that hitting one is like punching a bag full of bricks.
Today’s invention is a punchbag which has symmetrical ends. Each end has a zippered closure containing a set of suspension chains.
After each week’s use in a gym, the chains can be zippered into their envelope and the opposite end opened up to hang the bag.
Inverting the bag periodically should greatly lessen the hardening effect -allowing longer workouts and helping avoid injuries to hands and wrists.