The Simply Silent DX100 twin-speed extractor fan with wall kit features Ghost Air Movement Technology designed to deliver near silent ventilation. Meeting the latest building regulations this 4" (100mm) fan is specifically designed for use in bathrooms, shower rooms and ensuites. Requiring a 100mm diameter hole the Simply Silent DX100 is an ideal replacement for old noisy fans or as a new installation. The fan has a choice of two speeds that can be set to extract 15 or 21 litres of air per second and with innovative Ghost Air Movement Technology delivers low noise levels of 22 or 34 decibels @ 3 meters ensuring minimum noise irritation (15 litres per second at 22 dBA or 21 litres per second @ 34 dBA).