Fanmaster Indirect Diesel Fan Heater 50kw IDH2-50INThe powerful Fanmaster 50KW (170,600 BTU) Indirect Fired diesel heater produces an instantaneous heat that uses a flue system positioned on top of the heater to allow the fumes to escape which creates a cleaner dry heat which is ideal for confined spaces or areas with limited ventilation. Ducting can be attached to the flue to exhaust the fumes out. This unit must be used in well ventilated areas when not using the flue system and is for industrial