The Byrna HD is not a firearm*, but is an incredibly powerful and effective self-defense weapon for men and women of all ages and abilities. Powered by compressed air (CO2), the Byrna HD shoots .68 caliber round kinetic projectiles and chemical irritant projectiles that can disable a threat from up to 60-feet away. The no-recoil, easy-to-use, lightweight design of the Byrna HD makes it easy to learn and fun to shoot, always ready to go. With our patented design the CO2 cartridge is not pierced until you pull the trigger, leaving your Byrna HD in an indefinite ready-state. (less)