The Katana Plus rectangular duct fan with backward curved centrifugal impeller is available in sizes from 400x200mm to 1000x500mm and cover duties up to 3.1 cubic meters per second flow rate and 920 pascals pressure, and can operate in temperatures up to 70°C. All units are fitted with AC external rotor motors which run via a 230v single phase or 400v three phase feed, depending on unit size. The motor drives a backward curved centrifugal impeller which is made from aluminium. The casing is made from folded pre-galvanised sheet steel and is insulated with the addition of acoustic medium on the sides. All units have a swing out type casing.