Joint weights include models that are placed around the wrists or ankles. Certain models are primarily designed for wrist joints, as they have an additional hole/slit at the end to extend the thumb, providing minimal movement of the entire weight along the forearm. This makes the training more effective, especially for air boxing or exercising shoulders, arms, or the upper body. They are made of neoprene and filled with sand or iron beads, available in pairs and in various weights.