The only thing that you have to have to use HPA is an HPA tank. You can look into regulators as that will allow you too only use the pressure you need, but you dont have to have anything besids the tank.
I know they have built in regs but getting a dual reg set up will work best and can be used on other markers.Javaman said:Actually all HPA tanks have built in regs but the cheaper ones aren't adjustable (they output a set 850 or whatever). It's debatable which would be cheaper... A more expensive tank with an adjustable one or a cheap tank with preset reg and an additional one to finetune it.