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🌬️ Seal in comfort, shut out the noise — ventilation perfected.
The neverest® RK 4 inch Backdraft Shutter is a premium galvanized steel ducting connector designed exclusively for metal ducts. Featuring aluminum damper blades, stainless steel springs, and a rubber sealing ring, it ensures automatic, silent closure to prevent backflow of air. Ideal for HVAC, whole-house ventilation, and heat recovery systems, this 100mm duct fitting combines durability with quiet efficiency, backed by over 40 years of ventilation expertise.




| ASIN | B011INHF5A |
| Best Sellers Rank | 97,799 in DIY & Tools ( See Top 100 in DIY & Tools ) 419 in Registers, Grilles & Vents |
| Brand | neverest |
| Colour | Silver |
| Connector Type | Pipe connector |
| Connector type | Pipe connector |
| Country of Origin | China |
| Customer Reviews | 4.4 out of 5 stars 2,068 Reviews |
| Exterior Finish | Aluminium |
| Item Dimensions | 57 x 52 x 40 centimetres |
| Item Weight | 140 Grams |
| Item dimensions L x W x H | 57 x 52 x 40 centimetres |
| Manufacturer | neverest |
| Material | Alloy Steel, Rubber, Stainless Steel |
| Number of Pieces | 1 |
| Part Number | 40545030039031 |
| Size | 100mm |
| Thread Size | 100 |
| Thread Type | UN |
| Unit Count | 1.0 count |
R**.
Solid build, perfect
Quality build. Spring perfect resistance. Installed into Cooker Exhuast. Fan 1 and the flap open nearly half, But if fan 2or 3 the flap open full. No draft air coming inside at all.
M**S
Worth the money
Does the job perfectly. Well made and easy to fit. Quiet - no noise opening and closing. Well engineered. Would definitely say worth the money
B**R
Cheap and effective
Some have commented that the flaps don't close. I've installed these on three fan / ventilation pipes and they all work fine. I install with the hinge vertically, so the flaps open like doors and close easily. I put them on the exit side of the fan, so the maximum force pushes them open, because in strong winds backdraft can push them shut.
A**N
Brilliant!
After numerous plastic backdraught shutters this one really does work. Installed vertically in my cooker hood which vents through the roof. There is the occasional flap noise when the wind is high but this is preferably to a constant down draught into the kitchen. Low setting on the hood is sufficient to lift the flaps and expel smells and steam. Overall - really pleased and seems built to a good standard.
M**S
Works!
Easy to fit on top of the ceiling extractor fan. OK, I had to change the associated fittings a bit, but the job was done and dusted within an hour. Since then (about three weeks ago) there has been no rattling in the wind and the fan is working better than it did before.
D**K
Good product let down by design.
This product seems quite well made for the price. It has rubber dampers to stop tapping / rattling noises and closes completely and opens sufficiently wide that the existing ceiling fan is more efficient. I ordered this after measuring the existing fan and checking the technical specifications of the existing ceiling fan. The tubing that the draught excluder is built into is precisely the size of the fan (100mm). Logic would determine that it would be 2-3mm larger at the end that attaches to the fan so it can slide on making a neat and airtight seal. Instead, it sits exactly on top of it. This would be a huge problem on a horizontal fan. I’ve had to tape this in place to make a seal and prevent it moving when the fan is in use or air blowing through the ducting from outside. This is the reason for the lower stars or it would most likely get 4/5. Good product let down my illogical design flaw.
G**N
Quiet operation
Great product have tried numerous different products and this seems to work best for me
V**R
Nice little unit
Installed this in my loft, connecting it to a vent pipe running out from the kitchen hood. Works perfectly and the shutters open even when the fan is on its very slowest speed. Do keep it vertical when installing the unit as this is what it was designed for.
R**S
Excelente compuerta de aire (no retorno)
Muy buen producto, cumple su función a la perfección, sin embargo solo debe utilizarse en horizontal, no apto para usarse verticalmente.
L**E
Impeccable
Diamètre respecté mais ressorts un peu forts
J**H
Qualität bestens. In Dunstabzugsrohr verbaut und öffnet auch in geringster Stufe
Qualität ist absolut einwandfrei. Öffnet schon auf Stufe 1 meiner Abzugshaube. Ist zwar etwas kleiner als der Rohrinnendurchmesser, dafür passt es aber rein und kann ggf. mit Panzertape ausgeglichen werden. Ich bin damit sehr zufrieden.
D**L
Très bonne qualité
Facile à installer, fait le job, reste à voir sur la durée.
H**L
Ok
Enl spec. Snabb leverans
Trustpilot
4 days ago
2 weeks ago