The Active Air COSYS CO2 regulator system allows you to maintain ideal CO2 levels for optimum growth and even dispersal in your 10 x 10 feet indoor garden. It features an accurate, easy to adjust CO2 flow meter, a pre-set regulator that never needs adjusting, and a solenoid valve. Each unit also includes a dual outlet timer (TM01015D), three feet of flexible feeder tubing, and 15 feet of distribution tubing. The flow rate is adjustable from 0.2 to 2 cubic feet per hour. The solid brass fittings and rugged design will stand up to the harshest greenhouse environments!