Johnson’s LP Gas Stainless Steel CO2 Generator is the brand’s classic ceiling‑hung, liquid‑propane model built with a stainless housing for durability in humid grow rooms. It enriches greenhouse air up to 1,500 ppm in spaces around 4,800 sq ft (assuming one air change per hour). On LP gas it produces about 72 cubic feet of CO2 per hour at 60°F (roughly 8.25 lb/hr) with a burner range of 20,000–60,000 BTU/hr. The unit measures approximately 18 inches in diameter by 20 inches high, and ships at about 25 lb. A 24‑V gas valve with flame‑safety shut‑off is standard; operation requires a separate transformer, and an optional PPM controller/timer is available. Made in the USA by Johnson Gas Appliance Co.