This DiversiTech Drain Gun will save you money, time, and the additional pains that come along with cleaning out A/C condensate lines. The gun is small enough to fit in many tight, hard to reach places. It uses Swoosh CO2 gun cartridges for its ammo to deliver a strong blow to clear out any clogged drains. It uses carbon dioxide which is a much safer choice than using refrigerate to clean the drain lines. This blaster is powerful and is powered only by air, eliminating the mess caused by water back flushing drain lines. The instructions for use are simple - unscrew cup and insert cartridge with narrow end up, screw the cup slowly into the head until the cartridge contacts the puncture pin, quickly and firmly screw the unit together to puncture and seal the cartridge in the same motion, release the red safety catch, and depress the lever to discharge the Swoosh CO2 cartridge. For condensate drains, a quick and full discharge is the best. Say goodbye to wasting money and hours trying to clean and remove clogs from your drains. This powerful HVAC Drain Gun is a one stop shop for effectively blow out condensate drain lines instantly.