The HDX is powered by a single 12-gram non-threaded CO2 cartridge that is housed in a quick piercing housing so the HDX can be kept ready for use at a moment's notice without a constant charge on the valve seals. The HDX holds 16 quantity .68 caliber pepper or rubber rounds in its internal magazine. The fast pump action ensures you will have follow-up shots at the ready as fast as you can pump the action. The P2P HDX can also be powered by a single 88 gram cartridge which is convenient for training and practice scenarios. The HDX uses a ghost ring-type sight with a bright fiber optic element on the front sight blade. Expect velocity for the .68 caliber projectiles to be around 425 FPS and have an effective engagement range of up to 60 feet.