Includes:• Explosion-proof, 20,000 BTU air conditioner. • Explosion-proof, 12,000 BTU heater.For use with 12- and 16-drum fire-rated or 387- and 506-cu ft Agri-Turf™ lockers only.Notes:• For optimum temperature control, the appropriate size R-11 insulation package must be ordered when unit is purchased in conjunction with fire-rated models. • This accessory must be purchased in conjunction with a locker to ensure proper installation and to retain FM-approval. • Not available on Non-combustible l