HP Series Heat Exchanger Unit Heater is extra heavy duty (including heavy gauge steel construction) to meet the most demanding service and long life requirements for rugged industrial applications, such as space heating and liquid cooling. The HP Series heaters are suitable for a wide range of heating fluids including steam, hot water, glycol, oil, etc. Explosion-proof models suitable for hazardous locations are available on custom order. Engineered for ease of maintenance, all parts are easily removed. All fasteners are plated cap screws; no sheet metal screws are used. Heat exchanger cores are of steel construction with tension wound, close fitting aluminum fins. They are resistant to corrosive agents.