Xpelair 89994AW 9-inch high performance two speed extract or intake window fan with an internal shutter. This unit is operated by an external on/off switch or sensor and can be reversed or speed controlled with a compatible controller. The GX9 fan is reversible and feature totally enclosed external rotor motors providing constant volume outputs, even in gusty external conditions. The pre-balanced sickle bladed impellors eliminate `fan judder” and ensure quiet trouble free operation and the sealed for life maintenance free bearings ensure suitability for running at any angle. Running costs are impressively low, and when not in use the silent electro-thermal shutter cassette closes silently against backdraughts. GX9 unit has a tamper-proof positive plug and socket assembly which provides a means of isolation for service access. Installation in single and sealed double glazed windows (up to 25mm) is rapid using Xpelair”s unique metal ladder strip/screw system, ensuring a secure and watertight seal against the glass.