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 6135-00-016-0071
NSN 5985-01-194-5736
NSN 5950-00-598-9791
NSN 6620-01-463-1373
NSN 6110-01-496-4473
NSN 5930-01-185-9166
NSN 6110-00-431-6898
NSN 6320-01-162-5977
NSN 6105-01-481-8481
NSN 5855-00-221-9435
NSN 5965-01-127-0389
NSN 5895-01-557-0669