Ainiv Funny Face Squeeze Stress Balls, 20pcs Stress Relief Ball, Sensory Stress Ball for Kids and Adults, Hand Exercise Stress Relief Balls, Squeeze Toys for Anxiety, Fidget, Tension, Manage AngerSTRESS RELIEFThese stess balls with an ideal size for single hand seizing. And the finger squeezing action helps exercise fingers and wrists, promotes blood circulation, and the ergonomic design relaxes the body and mind, also relieve tension and eliminate anxiety. PREMIUM MATERISLThe stress ball is made of PU polyurethane material. The size of each ball is about 4. 5cm in diameter, it features stain resistant, durable, tear resistant and non toxic