The Byrna SD (Self Defense) is the successor of the Byrna HD. It has been re-engineered for optimal performance. Powered by compressed air (CO2), the Byrna SD shoots .68 caliber round kinetic and/or chemical irritant projectiles that can disable a threat from up to 60-feet away. It is an incredibly powerful and non-lethal self-defense weapon.Features: Up to 300 feet per second (204 MPH) projectile speed Ergonomic honeycomb grip for better control in all conditions Improved sights for faster target acquisition Straight trigger with a 6.5 lb. trigger pull weight on the second shot and smoother press Ambidextrous safe/fire switch that allows for easy toggling for both left-handed and right-handed individuals