Our box of ten 8g CO2 cartridges are custom fit for the Byrna HD. Now including 1 CO2 cartridge with oil for simple maintenance every 10 CO2 cartridges used. Each cartridge (new) will be good for 15-20 rounds (4 mags in a 5 round magazine) at full speed. Punctured cartridges within the Byrna HD will leak over time. It is recommended to swap out punctured CO2 cartridges and leave an un-punctured cartridge inside the Byrna HD to avoid any compressed air loss. The Byrna HD will puncture and fire the first round at the same time.
This product contains chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. www.P65Warnings.ca.gov