This is a silent ball cast by the "physical foaming" process. It has tens of millions of micro pores "to absorb the sound of walking, and solid ball bodies do not need to pump up. Environmentally friendly polyurethane integrated injection molding has 3c certification. Advantages: it is a pat ball that can be played at home. My brother and sister can play at ease. My brother and sister sleep at ease, and you don't have to worry about disturbing downstairs, exercising and playing, decompressing silently, not hurting the floor, and not hurting when hitting, washable. Deficiency point: if the elasticity does not meet the expectation, you can rub the ball and discharge the air in the ball to make it full of elasticity.