This 5-count box of 8-gram CO2 cartridges will power up your HDP 50 Compact through a thorough training session and allow to save a few cartridges for use in emergency situations. CO2 cartridges like these can be stored indefinitely in a dry, cool place. To ensure the long life of P2P Pepper Gun put a drop of silicone oil on the tip of each CO2 cartridge before installing it into the pistol.