- SHORE A
- ±5 pts against the specified hardness
- TENSILE
- Per compound datasheet, ASTM D412
Pads, Stoppers & Caps · Made to order
Air Extractor Flap — One-Way Cabin Pressure Relief
A moulded rubber one-way flap that lets cabin air out and nothing back in. It relieves the pressure the HVAC blower builds, lets a slammed door close cleanly, and seals against water, dust, fumes and road noise the moment the pressure drops. Soft enough to lift at almost nothing — typically 40–50 Shore A.
- HARDNESS
- 40–50 Shore A typical, 30–70 available
- TEMPERATURE
- −40 to +140 °C (EPDM)
- THICKNESS
- Flap thickness — to your drawing
- OPENING PRESSURE
- To your specification
- APERTURE
- Opening size and number of flaps
- MADE TO ORDER
- ISO 9001:2015
- 09111526A
Product gallery
Visual Reference
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Cross section viewSection through the flap and its seat — on request under NDA
- Max width
- Aperture size
- Thickness
- Flap thickness
- Number of flaps
- Two, four or six flaps in one frame — to your drawing
- Opening pressure
- To your specification, verified on first article
- Sealing at rest
- Water and dust ingress resistance with no airflow
- Mounting
- Bonded to a frame, clipped, or moulded with an integral hinge
Section drawing available on request. Send the aperture size, the number of flaps and the opening pressure you need — or a sample extractor and the vehicle it fits — and we will return a dimensioned drawing for approval.
Technical specifications
Engineering Data
- Product Family
- Pads, Stoppers & Caps
- Material
- EPDM standard; neoprene where specified
- Hardness (Shore A)
- 40–50 typical, 30–70 available
- Tensile Strength
- Per compound datasheet, ASTM D412
- Elongation at Break
- Per compound datasheet, ASTM D412
- Operating Temperature
- −40 to +140 °C on EPDM
- Compression Set
- Tested to ASTM D395 Method B
- Density
- Per compound datasheet
- Colour Options
- Black standard, custom RAL on request
- Lead Time
- Confirmed with the quotation, from approved drawing and approved sample
- Opening pressure
- To your specification, verified on first article
- Flap thickness
- To your drawing
- Number of flaps
- To your drawing
- Sealing at rest
- Water and dust ingress with no airflow
- Ozone and UV resistance
- Required — EPDM or neoprene
- Certifications
- ISO 9001:2015 — certificate 09111526A, valid to 21 February 2027
- Minimum Order
- 10,000 pieces per part number, per compound, or quoted against the part where geometry or tooling makes that unrealistic. Prototype and first-article lots sit outside the minimum.
Dimensional reference
- Max width
- Aperture size
- Thickness
- Flap thickness
- Number of flaps
- Two, four or six flaps in one frame — to your drawing
- Opening pressure
- To your specification, verified on first article
- Sealing at rest
- Water and dust ingress resistance with no airflow
- Mounting
- Bonded to a frame, clipped, or moulded with an integral hinge
Available materials
Rubber Compound Options
Select the compound best suited to your operating environment and application requirements.
| Rank | Compound | Temperature | Why, for an exposed one-way flap |
|---|---|---|---|
| Recommended | EPDM | −40 to +140 °C | Ozone, UV and water resistance, and it stays soft at −40 °C — which is when a flap most needs to open |
| Suitable | Neoprene | −40 to +120 °C | Reasonable weathering and ozone resistance. Stiffer cold than EPDM, so the opening pressure rises in winter |
| Suitable | Silicone | −60 to +220 °C | Excellent cold flexibility and weathering — a real option near a heat source. Tears more easily, which matters on a thin flap |
| Not recommended | NBR | −30 to +120 °C | Cracks in ozone and UV — not for an exposed flap. Specify only where the flap is fully enclosed and sees oil mist |
| Not recommended | SBR | −30 to +100 °C | Also poor in ozone and UV, and no better cold |
| Available | Natural rubber | −20 to +90 °C | Excellent flexibility and tear strength, but it perishes outdoors faster than any of the above |
| Not recommended | FKM · AEM | See the compound table | Stiff, expensive and unnecessary for a ventilation flap |
Not sure? Send the medium, temperature and load
FLAP HARDNESS
40–50 Shore A
soft enough to open, firm enough to seal
Key advantages
Why Specifiers Choose Margo
Air out, nothing in
The flap lifts on cabin pressure and drops the instant it falls. Get that balance wrong and you either trap air — heavy doors, weak vents — or let water and fumes back in. We tune it with thickness and hardness, not guesswork.
It has to work at −30 °C too
Rubber stiffens as it cools, and a flap that will not lift on a winter morning makes doors hard to close. EPDM is our default here because it stays soft cold — not just because it resists weather.
It must not buzz
An extractor flap that flutters at speed is a warranty complaint, not a leak. Flap thickness, hardness and seat geometry decide it — tell us the airflow and we will tune the three together.
Exposed for the life of the vehicle
Behind a bumper the flap sees rain, road spray, sunlight and ozone. Nitrile and SBR crack in those conditions — we mix EPDM for this part, and we will say so even when a cheaper compound is asked for.
Industries served
Global Applications
Automotive
Cabin pressure relief behind the rear bumper and in quarter panels, on passenger cars, vans and buses
Electrical & Enclosures
The same valve does the same job on an outdoor cabinet — letting warm air out while keeping rain and dust from following it back in
Heavy Industry
Cab ventilation on plant and agricultural machinery — where the cab is pressurised to keep dust out and the flap is what makes that work
Infrastructure
Ventilation flaps on site cabins and enclosures
Manufacturing process
From Compound to Certification
Material compounding
Polymer blending, additive integration and batch QC in our in-house lab. Hardness is set here, and on a flap it is the specification.
Mould design and CNC tool manufacture, in-house, held as a controlled record. The flap and its seat are cut together
The seat geometry is half of the sealing performance.
Compression Moulding
Hydraulic press cycles at controlled temperature and pressure profiles per product spec.
Post-cure and deflashing
Flash removed from the flap edge and the seat. Flash on a sealing edge holds the valve open.
Quality inspection
Hardness, flap thickness and opening pressure checked on batch samples, plus dimensional check.
Export packaging
Industrial packing with documentation. Flaps packed flat and uncompressed — a flap stored folded takes a set and will not seal. ISPM-15 treated pallets where timber is used.
Quality assurance
Certified to International Standards
Every product leaves our facility with a documentation package — material test reports, dimensional inspection sheets and a certificate of conformance — giving traceability from raw material to finished part.
ISO 9001:2015 · Certificate 09111526A
Integral Certification Ltd · Valid to 21 February 2027
Scope: rubber moulded components — this part is within scope
IATF 16949 — upgrade in progress, certification targeted by end 2026
ISO 14001 and ISO 45001 — targeted 2027
Production metrics
- Since 2005
- In operation
- 60+
- Active clients
- 3–4 weeks from approved sample
- Avg. lead time
Downloads
Technical Documentation
Dimensioned drawings and 3D models are issued on request, under NDA where required. Send the aperture size, the number of flaps and the opening pressure you need — or a sample and the vehicle it fits — and we will return a drawing for approval.
Request a drawingFAQ
Technical & Commercial Questions
Answers to the most common questions from engineering teams and procurement managers worldwide.
What is the minimum order quantity for this part?
We supply in bulk. The minimum run is 10,000 pieces per part number, per compound, or quoted against the part where geometry or tooling makes that unrealistic. Prototype and first-article lots sit outside the minimum.
Can you match a competitor specification or reverse-engineer an existing part?
Yes. Send the sample and, if you can, tell us what went wrong with it — a flap that stands open has taken a compression set, a flap that buzzes is too thin or too soft, and a flap that has hardened and split was the wrong compound rather than the wrong shape.
What file formats do you accept for drawings?
PDF, DWG, DXF and STEP. Mark the aperture, the flap thickness and the opening pressure — and say whether you want loose flaps or a bonded frame assembly, because they are different parts to quote.
Do you provide material test reports with each shipment?
Yes. Material test reports, dimensional inspection sheets and a certificate of conformance ship with every consignment. Hardness, tensile to ASTM D412 and compression set to ASTM D395 Method B are tested in-house, and opening pressure is verified on first article.
What are your payment and delivery terms for international orders?
TT and LC accepted, discussed per order. Ex-works Nashik or FOB Nhava Sheva. Commercial invoice, packing list and certificate of origin are issued with every consignment. Flaps ship packed flat, since a folded flap takes a set.
Same compound
Other parts we mould in the same compounds
- Bumper Stopper — Rubber Bump Stop · EPDM, Neoprene
- Foam Gaskets — Closed-Cell Sponge for Low-Closing-Force Seals · EPDM, Neoprene, Silicone
- Tailgate Switch Boot — Sealed Push-Button Cover · EPDM, Neoprene, Silicone
- Radiator Shroud Flaps — Sealing Out Cooling Air Bypass · EPDM, Neoprene, Silicone
- Slotted Packing Pad — C-Section · EPDM, Neoprene
- 3 Pin Hole Pad — Three-Way Electrical Pass-Through Grommet · EPDM, Neoprene, Silicone
Need this part quoted?
Send your drawing or a sample flap. Tell us the aperture, the airflow and the opening pressure you need. We confirm compound, hardness and flap thickness — and whether you want loose flaps or a bonded assembly — then quote against your annual quantity. We respond within 48 hours.