Profile: Callahan Thomas, LLC offers forced air unit heaters, explosion-proof electric unit heaters, duct heaters and steam blankets. Our heat exchanger unit heater is designed for steam applications that may be subjected to freezing conditions. It is provided with a rectangular top and bottom headers, which distort to a circular shape during accidental freeze-up, without serious damage. Heat exchanger cores are of steel construction with tension wound, close fitting aluminum fins, and are highly resistant to corrosive agents, including hydrogen sulfide. Our heaters are designed for rugged industrial applications including space heating and liquid cooling applications. Our corrosion-resistant wash down heaters are designed for wash down applications. Our heaters are provided with epoxy-coated fan blade and 16-gauge stainless steel cabinet for increased corrosion resistance.