What is the difference between CO2 and Compressed Air?
CO2 tanks are the original air source for paintball guns. CO2 tanks are 
filled with liquid CO2 and it is the pressure from this liquid turning 
to gas that powers the marker. 
CO2 paintball tanks
 are very inexpensive so they are popular with many players, especially 
beginners. Most paintball markers will get around 50 shots per ounce of 
liquid CO2. However, CO2 does have some drawbacks. CO2 pressure 
fluctuates with ambient temperature and how fast it is consumed. If you 
fire a long rapid string of shots your pressure will drop and the marker
 can freeze up. Your pressure starts to drop as your tank starts to get 
low. Liquid CO2 that gets siphoned into the marker is hard on the seals 
and many of today's markers cannot use CO2 at all without damaging the 
marker. Refer to your owner's manual or give us a call if you are not 
sure your paintball gun can use CO2.
The better option is HPA (High Pressure Air), also known as Compressed, N2 or Nitro systems. An 
HPA paintball tank
 is actually pressurized with compressed air instead of filled with a 
liquid. Paintball compressed air tanks typically are rated to 3000 psi 
and made of aluminum or 4500 psi and are carbon fiber or fiberglass 
wrapped. A 
paintball tank regulator on
 top of the bottle screws into your marker's ASA (Air Source Adapter) 
and regulates the pressure to your gun. A regulator's output is usually 
high pressure (800-850 psi) or low pressure (400-450 psi), depending on 
what you need for your marker. Aluminum 3k psi systems get an average of
 10 shots per cubic inch (ci), so a 48ci 3000 psi HPA tank will shoot 
around 450-500 shots per fill. They are inexpensive but heavy. Fiber 
wrap 4.5k psi systems get an average of 15 shots per ci, so a 48ci 4500 
psi system will shoot around 700-750 shots per fill. A 68ci 4500 psi 
compressed air tank will get approximately 1000-1050 shots.
Compressed
 air paintball tanks have several benefits. They are larger and bulkier 
than CO2 but deliver consistent pressure regardless of ambient 
temperature or how fast you shoot. This makes your marker function 
smoother and increases your shot to shot accuracy. Since no freezing 
liquid is present it is a lot easier on the inner seals of your marker. 
HPA will work on all paintball guns. If your local field can fill air 
tanks then HPA is the better way to go.