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100mm Gravity Shutter Black - 4 Inch Extractor Fan Vent

£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 black polycarbonate vent cover with three internal louvres that open under airflow and close by gravity when the extractor fan stops. Designed for installation on both internal and external walls, the shutter accepts 100mm rigid or flexible round ducting from standard 4-inch extractor fans.

When fitted to an external wall, the shutter prevents rain penetration and backdraught air from entering the ducting when the fan is off. The gravity-closed louvres also block vermin and windblown debris from accessing the duct run. In internal wall applications, the shutter acts as a one-way valve that allows extracted air to pass through to a plenum or adjacent space while preventing reverse flow when the fan is not running.

The 152mm square faceplate fixes directly to brickwork or masonry using screw fixings through the four corner mounting points. The 22mm recessed depth allows the shutter to sit partially into the wall opening, while the 38mm projection gives clearance for the louvre mechanism. The polycarbonate construction resists UV degradation in external installations and tolerates typical condensation in bathroom and kitchen ducting without corroding.

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

Product Specification Sheet

Frequently Asked

What size wall opening is needed?

The cut-out diameter is 105mm to accept standard 100mm ducting with a slight tolerance. The 152mm square faceplate then covers the opening and fixes to the surrounding wall surface.

Does the shutter require power to operate?

No. The louvres open passively under the airflow from the extractor fan and close by gravity when the fan stops. No electrical connection to the shutter itself is needed.

Can it be used on an external wall exposed to weather?

Yes. The polycarbonate construction resists UV degradation and the gravity louvres are designed to seal against rain penetration when closed. The shutter is specifically intended for external wall installation in typical UK weather conditions.

How is it cleaned?

Wipe the external louvres with a damp cloth to remove dust and debris. For internal ducting condensation buildup, disconnect the ducting from the rear and rinse the louvre mechanism with warm water, then allow to dry fully before reinstalling.

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 black polycarbonate vent cover with three internal louvres that open under airflow and close by gravity when the extractor fan stops. Designed for installation on both internal and external walls, the shutter accepts 100mm rigid or flexible round ducting from standard 4-inch extractor fans.

    When fitted to an external wall, the shutter prevents rain penetration and backdraught air from entering the ducting when the fan is off. The gravity-closed louvres also block vermin and windblown debris from accessing the duct run. In internal wall applications, the shutter acts as a one-way valve that allows extracted air to pass through to a plenum or adjacent space while preventing reverse flow when the fan is not running.

    The 152mm square faceplate fixes directly to brickwork or masonry using screw fixings through the four corner mounting points. The 22mm recessed depth allows the shutter to sit partially into the wall opening, while the 38mm projection gives clearance for the louvre mechanism. The polycarbonate construction resists UV degradation in external installations and tolerates typical condensation in bathroom and kitchen ducting without corroding.

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

    Product Specification Sheet

    Frequently Asked

    What size wall opening is needed?

    The cut-out diameter is 105mm to accept standard 100mm ducting with a slight tolerance. The 152mm square faceplate then covers the opening and fixes to the surrounding wall surface.

    Does the shutter require power to operate?

    No. The louvres open passively under the airflow from the extractor fan and close by gravity when the fan stops. No electrical connection to the shutter itself is needed.

    Can it be used on an external wall exposed to weather?

    Yes. The polycarbonate construction resists UV degradation and the gravity louvres are designed to seal against rain penetration when closed. The shutter is specifically intended for external wall installation in typical UK weather conditions.

    How is it cleaned?

    Wipe the external louvres with a damp cloth to remove dust and debris. For internal ducting condensation buildup, disconnect the ducting from the rear and rinse the louvre mechanism with warm water, then allow to dry fully before reinstalling.

    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.