Umarex Big Blast Cap Target Inflators are a fun way to use a non-explosive shooting target that merely operates by air pressure. Any high power gun will cause a big boom whether you’re using a .22LR, 9mm, .223, and even a high power air rifle. With a Big Blast Cap you can pump air into your plastic bottle and it is recommended to pump up to 80 psi depending on the weather and size of the bottle. The pressurized air immediately disperses to normalcy creating a “boom” as the air molecules rush out into the normal atmospheric pressure. This model includes a foot pump, 10 Big Blast Caps, two compatible air pump needles, one mesh drawstring bag and tie string. Oh, and the caps are reusable if you can find them!