MATERIAL: Made of 304 stainless steel, sturdy and hold up well to daily use SOLID STEEL BAODING BALLS: Stainless steel Baoding balls are often used in martial arts to improve both grip strength and mental discipline. Weighing about 520g for a pair of Baoding balls, heavy weight gives your hands a good workout HAND MASSAGE BALLS: A simple exercise that provides relief to your pain wrist and stiff fingers. Help with hands discomfort from the use of electronics devices GREAT FOR: Hand therapy, stress relief, concentration training and strength training. (Note: Practice close to and on top of a soft surface in case they fall out of your hand) Color: silver Size: 40cm in diameter Delivery Quantity: 1 pair