8 Gram CO2 Cylinders are only compatible with the Byrna CL / SD / EP & HD Models. *Not compatible with Byrna LE, CL-XL, SDXL, HDXL or Launchers with Byrna Boost Installed Our box of ten 8g CO2 cylinders are custom fit for the Byrna CL, SD, EP and HD Launchers. Now including 1 CO2 cylinder with oil for simple maintenance every 10 CO2 cylinders used. It is recommended to keep an unpunctured cylinder in your launcher at all times for self-defense purposes. Punctured cylinders within your Byrna Launcher will leak over time.