What is ANTI-SIPHON tank?
This tends to cause a lot of confusion. As mentioned above, a SIPHON tank is designed so that liquid co2 purposely comes out of the tank, when the valve is opened. However, an Anti-Siphon tank is designed to prevent liquid from coming out of a tank. Basically, an ANTI-SIPHON tank is the exact same thing as a REGULAR tank. Typically, paintguns that CANNOT use liquid, use an ANTI- SIPHON tank when they run a bottle in the horizontal position, where liquid might accidentally enter the gun. Since the Z is designed to run liquid, you should NEVER buy an ANTI-SIPHON tank.