LJ Wing manufacturers Heating, Ventilating, and Air Conditioning (HVAC) components ideal for controlling the temperature and quality of outside air for any commercial or industrial building. Products includes steam or hot water integral face and bypass coils, steam or hot water unit heaters, steam or hot water boiler combustion preheaters, steam or hot water air handling units, door heaters and air curtains, and industrial gas unit heaters. LJ Wing invented the integral face and bypass coil concept 50 years ago to protect air handler coils from freezing when handling large amounts of outside air.