The Zyllion ZMA-30vibrating peanut massage ball features a unique and innovative peanut shape that is designed to contour to many parts of your body. It works great to target muscles in hard to reach areas such as the calves, mid-upper back, glute muscles, hamstrings, spine, and neck. You can also hold the device in one hand and press it against various body parts to increase blood circulation and to reduce muscle tightness.