Comfort Zone CZTT2 Radiant Double Burner Propane Tank Top Heater, specially designed with a tip-over cutoff switch, a safety shut-off valve, and a safety metal grille. This heater features a durable metal construction with chrome grille, a variable heat output 18,000 - 30,000 BTUs, a match light ignition, and it can be used outdoors or indoors in well-ventilated spaces. This heater also provides immediate strong radiant heat, emitting strong heat up to 25 feet. It mounts directly to 20LB propane (LP) tank (not included). One tank provides approximately 14 hours of continuous operation. The safety shut-off valve stops propane flow if flames goes out.