XUEMEI Material: Made of 304 stainless steel, sturdy and durable, suitable for daily use. Solid Steel Baoding Ball: Stainless steel Baoding Balls are often used in martial arts to improve grip strength and mental discipline. A pair of Baoding balls weigh about 520 grams, which is heavy and can provide a good exercise for your hands. Hand Massage Ball: A simple exercise to relieve wrist pain and finger stiffness. Helps relieve hand discomfort caused by using electronic devices Ideal for: hand therapy, stress relief, focus training and strength training. (Note: Practice near a soft surface to prevent them from falling out of your hands) Color: Silver Size: Diameter 40 cm Shipping Quantity: 1 pair