CO2 Injection System SM 0.1 - 1 CFH

I bought this and set it up in about 5 minutes. I use a paintball co2 tank (20oz) and it should last 4.5 days with 12 hours of use per day, at .2 CFH. It came with a manual explaining how to calculate how much CFH I should set the unit at (Would have been useful BEFORE I bought it!) as well as how to figure out how long my co2 tank will last.
I plan on buying 2 or 3 more paintball co2 tanks so I can refill them while the other one is still in use.