The RF90BW is a single speed, 100mm duct, recessed centrifugal fan. Suitable for duct runs up to 10m long. It also comes with integral back draught shutter.
This is the 'B' model which is a single speed fan operated via a light switch or pull cord.
The RF90BW replaces the R90B. So if you have a R90B then this fan is its direct replacement and it will fit in the same space as your existing product and ducting.
The R90 range has been in production since the 1990's so the quality and durability of the fan has been proven and has stood the test of time.