These P2P 8 gram CO2 Cylinders will power up your HDP 50 Compact through an intense training session and allow you 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 your P2P Pepper Gun put a drop of silicone oil on the tip of each CO2 cartridge before installing it into the pistol. 8 Gram Non-Threaded CO2 Cartridges 5 Cylinders Fits P2P HDP 50 Compact