High quality expansion chamber has 4 stages of expansion. Easily converts liquid CO2 into a gas for more even air pressure to your valve. Keeps your gun from freezing up and your shot velocity much more consistent. Increases the life of your internal seals, reduces drop off in cold weather and velocity spikes in hot. Improves your paintball marker"s efficiency and reduces ball breakage. Gun, hose and fittings are NOT included. Bright Chrome.