Galvanized steel sheet structure. Impeller with aluminium hub and wing profile bladesmade of thermoplastic PPG resin. PST shock-resistant thermoplastic material protection dome. Steel safety grille. Eye bolts suitable for lifting the fan. Self-ventilated motor – Class F – IP55 – “LONG LIFE” ball bearings. For continuous operation in environments with air temperature range -25°C ÷ +50°C. 2 speed motor models can be controlled by a three-phase polarity switch, not supplied as an accessory but easy to find on sale. ACCESSORIES:Phase slicing speed regulator for monophase motors. Backdraught gravity shutter. Safety switch supplied as an accessory but already built on the fan motor as standard.