Gotham Hydroponics 4-Burner Carbon Dioxide Generator, Liquid Propane 4 Burner unit is recommended for a 20ft x 20ft area (400 sq. ft.), Unit is compatible with Liquid Propane (LP) only Dual solenoid valves, Precision manufactured clean firing brass burners Solid state electronic ignition module - no pilot light necessary, Tip over switch shuts off gas if unit falls or tips over Convenient On/Off switch, Includes hanging hardware and Allen key wrench Features gas intake regulator and hose