The Model IDHB duct heater is configurable for most applications in sizes up to 36 by 36 inches. It features a 50- or 60-Hertz design, fan interlock, power terminal block, control board, grounding lugs, an automatic limit switch for primary over-temperature protection, and a manual reset limit switch for secondary over-temperature protection. Typical applications include space, primary, secondary, auxiliary, and reheating. All heaters from Greenheck are UL/CSA-listed and many options are available.