Airburst MegaBoom Supersonic Target System (STS) Includes oil-filled air pressure gauge Attach plastic soda or water bottles for some shootin' fun! Shooter and all other people in the area should be at least 15 feet from the STS when the bottle is shot Directions included Up to 150 decibels of boom! According to the manufacturer, lightweight pellets will penetrate the bottles and exhaust all the air but will not cause a supersonic boom (the bottle doesn't blow up). In .22 caliber, they told us that the lightest pellet that blows up the bottle and causes a boom weighs 14.3 grains. They have not provided a minimum-weight projectile for any other caliber. However, the manufacturer states that slingshot ammo will blow up the bottle (and cause a boom), which suggests that the weight of the projectile is more important than speed. Your Airburst MegaBoom Supersonic Target System (STS) will add some boom to your range! If you like reactive targets, then the Airburst MegaBoom Supersonic Target System (STS) will deliver that in spades! Attach a 1-liter or 2-liter plastic soda or water bottle to your STS platform, hook up a low-pressure bicycle hand pump to the input and pump up the bottle. Extensive directions are included with your system. Read all directions before using your STS. The shooter and everyone in the general vicinity should wear safety glasses and hearing protection. Remember to remove all pets from the area to protect them from the supersonic boom, flying plastic shards and inhaling the misting BoomDust.