Xpelair Wx12 High Performance Intake/Extract Axial Ventilation Unit. Choice Of Optional Controllers. Suitable For Single, Cavity Brick And Current Timber Frame Walls. Balanced External Rotor Motor And Impeller For Quiet Efficiency. Sealed For Life Maintenance Free Bearings, Suitable For Running At Any Angle. Built-In Silent Action Electro-Thermal Shutter Cassette. Passive Trickle Vent Facility For Background Ventilation With Fan Off Ultra Slim High Gloss Abs Fascia With Integral Finger Safety Guard. Shadow