So first its "NOS" and now its CO2? Why the hell do you need 4 bottles? Just buy a go-kart kit and call it a day... it includes CO2 catridges, hose, and gun grip CO2 release. This is what these go kart people use as their "NOS". You can take off one of your windshield nozzle hoses and plug the hose right there so there's your purge. You sit in the car show with this device in your hand that looks like a grenade spraying CO2 at your windshield... yay CO2 and iced out window! LMFAO