The ventilation heater will be type ii per mil-h-16235, which requires nonmagntic construction, non magnetic material, tube has 60 fins per ft.
A heat transferring unit utilizing a separate source of steam or hot water as the heat transfer medium. It consists of finned parallel tubes joined together by a header or headers and is designed for installation in the ducts of a forced air circulating system. It may be provided with a flanged outer casing to facilitate mounting of the unit in planned or existing duct work. Circulation of the heated air is achieved by use of a blower or fan not integral with the heating unit.
Classification: Air heaters and hot air distributors, not electrically heated, incorporating a motor-driven fan or blower, and parts thereof, of iron or steel
NSN 6150-01-462-0202
NSN 5945-01-085-6446
NSN 5930-01-181-5605
NSN 5996-01-297-1564
NSN 6220-00-967-0062
NSN 6135-01-648-4875
NSN 5975-00-827-0261
NSN 6320-00-823-2015
NSN 6240-00-984-3354
NSN 5925-01-043-2334
NSN 5985-00-702-8877
NSN 5910-00-274-3189