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100mm Gravity Shutter for Extractor Fans - White

£399
The RRP is the manufacturer's recommended retail price of the item.
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Description

The Knightsbridge 100mm gravity shutter is a wall-mounted backdraught prevention fitting designed for 100mm (4-inch) round extractor fan installations. Three internal gravity-operated flaps close when the fan is off, blocking backdraught air, rain, and vermin from entering through the duct. When the fan runs, airflow pushes the flaps open, allowing extraction to proceed normally.

Designed for installation on external walls where 100mm round ducting terminates, the shutter fits both rigid and flexible round duct types and requires a 105mm diameter cut-out in the wall. The white polycarbonate construction withstands outdoor exposure without rust or corrosion, and the 152mm square faceplate covers the cut-out and secures to the wall with the four recessed fixing points at each corner.

The 38mm projection from the wall when surface-mounted includes the flap housing depth, while the 22mm recessed depth indicates how far the fitting sits into the wall when flush-mounted into a recess. The gravity-operated flaps require no manual intervention or electrical connection — they open and close purely in response to airflow direction, making them a reliable passive solution for kitchens, bathrooms, utility rooms and toilet compartments with intermittent extractor fan use.

Specification
Height 152 mm
Width 152 mm
Projection 38 mm
Recessed Depth 22 mm
Cut-out Diameter 105 mm
Construction Polycarbonate
Finish White
Warranty 1
Downloads

Product Specification Sheet

Frequently Asked

What fan size is this compatible with?

The shutter is designed for 100mm (4-inch) diameter extractor fans with round ducting. It fits both rigid and flexible duct types that terminate at 100mm diameter.

How does the gravity shutter prevent backdraught?

Three internal flaps close under their own weight when the fan is off, blocking reverse airflow, rain and debris. When the fan runs, the airflow pushes the flaps open. No manual operation or electrical connection is required.

Can this be installed flush with the wall?

Yes. The 22mm recessed depth allows the shutter to sit partially into the wall when installed into a recess. Surface mounting is also possible, with a total projection of 38mm from the wall face.

What wall cut-out size is needed?

A 105mm diameter circular cut-out is required. The 152mm square faceplate then covers this opening and fixes to the wall at the four corner points.

Shipping & Returns

Free worldwide delivery

Free worldwide delivery on all orders over £99. International orders for third-party brand products may be subject to an additional courier surcharge based on volumetric weight, particularly on larger lighting fixtures — if a surcharge applies, our team will email you with the amount before dispatch and you can proceed or cancel for a full refund. See full delivery terms.

Returns

30-day returns window from delivery. As all our products are electrical or lighting goods, returned items must be inspected and recertified by a qualified electrician before resale — the cost of this inspection (25–40% of the item value) is deducted from your refund. Customers pay return shipping. Made-to-order, special-order and clearance items cannot be returned. See full returns policy.

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    Description

    The Knightsbridge 100mm gravity shutter is a wall-mounted backdraught prevention fitting designed for 100mm (4-inch) round extractor fan installations. Three internal gravity-operated flaps close when the fan is off, blocking backdraught air, rain, and vermin from entering through the duct. When the fan runs, airflow pushes the flaps open, allowing extraction to proceed normally.

    Designed for installation on external walls where 100mm round ducting terminates, the shutter fits both rigid and flexible round duct types and requires a 105mm diameter cut-out in the wall. The white polycarbonate construction withstands outdoor exposure without rust or corrosion, and the 152mm square faceplate covers the cut-out and secures to the wall with the four recessed fixing points at each corner.

    The 38mm projection from the wall when surface-mounted includes the flap housing depth, while the 22mm recessed depth indicates how far the fitting sits into the wall when flush-mounted into a recess. The gravity-operated flaps require no manual intervention or electrical connection — they open and close purely in response to airflow direction, making them a reliable passive solution for kitchens, bathrooms, utility rooms and toilet compartments with intermittent extractor fan use.

    Specification
    Height 152 mm
    Width 152 mm
    Projection 38 mm
    Recessed Depth 22 mm
    Cut-out Diameter 105 mm
    Construction Polycarbonate
    Finish White
    Warranty 1
    Downloads

    Product Specification Sheet

    Frequently Asked

    What fan size is this compatible with?

    The shutter is designed for 100mm (4-inch) diameter extractor fans with round ducting. It fits both rigid and flexible duct types that terminate at 100mm diameter.

    How does the gravity shutter prevent backdraught?

    Three internal flaps close under their own weight when the fan is off, blocking reverse airflow, rain and debris. When the fan runs, the airflow pushes the flaps open. No manual operation or electrical connection is required.

    Can this be installed flush with the wall?

    Yes. The 22mm recessed depth allows the shutter to sit partially into the wall when installed into a recess. Surface mounting is also possible, with a total projection of 38mm from the wall face.

    What wall cut-out size is needed?

    A 105mm diameter circular cut-out is required. The 152mm square faceplate then covers this opening and fixes to the wall at the four corner points.

    Shipping & Returns

    Free worldwide delivery

    Free worldwide delivery on all orders over £99. International orders for third-party brand products may be subject to an additional courier surcharge based on volumetric weight, particularly on larger lighting fixtures — if a surcharge applies, our team will email you with the amount before dispatch and you can proceed or cancel for a full refund. See full delivery terms.

    Returns

    30-day returns window from delivery. As all our products are electrical or lighting goods, returned items must be inspected and recertified by a qualified electrician before resale — the cost of this inspection (25–40% of the item value) is deducted from your refund. Customers pay return shipping. Made-to-order, special-order and clearance items cannot be returned. See full returns policy.