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Please note that 4" 100mm shutters have 1 spring and not 2. This is correct as 2 springs would offer too much resistance Fit the shutter with the centre spindle of the flaps in a vertical position and make sure ducting is level, Manufacturer: fans4less
Please note that 4" 100mm shutters have 1 spring and not 2. This is correct as 2 springs would offer too much resistance Fit the shutter with the centre spindle of the flaps in a vertical position and make sure ducting is level, Manufacturer: fans4less