Kime bag

A kime bag is a small, tough, conditioning bag for all martial arts, especially kung fu. The 6 1/2 inch (165 mm) bag swings freely from a heavy-duty chain to help improve hand-eye coordination, while strengthening and toughening the user's fingers, hands, forearms, and elbows.

Sometimes filled with shot, beans, and lead to a weight of 5 lb (2.3 kg), it swings around naturally when hit, forcing the user to focus on hitting the moving target with his fist, elbow, or forearm. It is cheap to purchase one, and also easy to make.