Meridional acceleration design with drum or straight duct, tapered hub, and twisted airfoil blades; stel impeller with balance grade ⩽G5.6; low noise, energy-eficient, compact, horizontal or vertical installation.Supply and exhaust ventilation for industrial and civil buildings.Silencer type:GXF-BX1 (silencers at inlet & outlet) /GXF-BX2 (silencers on casing, inlet & outlet); roof-mounted version (add suffix "W").Two-speed motor

for two-step adjustment; VFD motor and controller for stepless speed regulation.Corrosion-resistant and explosion-proof versions available for corrosive, flammable, and explosive gas handling.