Steel body with epoxy resin coating. Backward-curved impeller in galvanized steel, statically and dynamically balanced. Protection dome made of high density structure plastic material and particularly resistant against the atmospheric agents corrosion action. Self-ventilated motor, Class F – IP55, with “LONG LIFE” ball bearings, mounted outside the air flow. For continuous operation in environments with max temperature 60°C. Eye bolts for lifting up, supplied from the ATR 500 model onwards. 2 speed motor models can be controlled by means of the three-phase switch, not supplied as an accessory, but easy to find on sale. ACCESSORIES:Phase slicing speed regulator for monophase motors. Counter-basement. Backdraught gravity shutter.