12 Gram CO2 Cartridges are only compatible with the Byrna HD when you have a Byrna Boost Adaptor installed.
Our box of ten 12g CO2 cartridges are a custom fit for the Byrna HD with the Byrna Boost 12g Adaptor. Increases shot capacity to 20 rounds per cartridge. 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.