Use an air pump to inflate and inflate the ball until it reaches a diameter of 40 cm. Then close the pumping point with the supplied cap. After a while, the elastic material expands and reaches a size of 50 cm in diameter. If you can, you can blow the ball full with a compressor, but slowly and carefully. Jump only on a flat surface or lawn, it is for your own safety. Fill the ball with warm air, about 20c. The product can only be inflated by an adult. The size and use of the product are not intended for adults.