SpectraCool with Advanced Corrosion Protection Solutions provide industry leading corrosion protection to components critical to the performance of the air conditioner. For applications where air conditioners are exposed to harsh, corrosive, chemical elements. Hoffman utilizes advanced coatings to protect the critical components, extending their life and optimizing the extended performance level of the product. Features: Attractive industrial design with minimal use of visible fasteners; Level 1 Protection Includes: Protective coatings only applied to copper tubing and coils on the condenser (exterior facing) side as well as thermostat coatings; Energy-efficient rotary compressor on most models; Level 2 Protection Include: Everything that was coated in Level 1, plus protective coatings applied to the evaporator (interior facing ) side and an additional wrap around the thermostat; Cleanable, reusable aluminum mesh filter included to protect coils for maximum cooling performance in dirty environments; R407C, R513A or R134a refrigerants; 115, 230 and 400/460 VAC 3-phase power input on most models; Reliable mechanical thermostat on enclosure side of the unit; All G-series come standard with two separate thermostats for cooling and heating when a heater is equipped; Operating temperature range from -40 F/-40 C to 131 F/55 C; Dust-resistant condenser coil allows the unit to be run filterless in most indoor applications; Dual condenser-side air movers for performance redundancy on G52 and G57 models; Galvanized or stainless steel cover for rugged factory and outdoor environments; Exterior and partially recessed mounting options; Galvanized sheet-metal cover for rugged factory and outdoor environments