Brass-Seal™ System / Patent Pending
Forged
Brass
Mail Slot
Block Out The Air
The finest entrances are never an accident.
Brass-Seal™ Forged Brass
Mail Slot System
ASTM E283 / Independently Tested
A Material Decision
The front door is the first material decision
a visitor encounters. It should be considered accordingly.
The mail slot is one of the most visible and one of the most consequential openings in a door. Whether specified as an exterior unit, an interior unit, or a complete paired system, the Brass-Seal™ system is engineered so each configuration independently restores the integrity of the door. No combination is a compromise.
Brass-Seal™ / Exterior Forged Brass Mail Slot
The Face
of the Door.
Solid forged brass face plate. A heat-resistant magnetic closure maintains consistent compression against the acoustic-lined cavity gasket with each delivery. The closure magnet is engineered for high-temperature performance, retaining approximately 90% pull strength at 212°F, a threshold relevant to direct sun exposure on dark or south-facing doors. A continuous perimeter gasket between the rear of the slot and the door face seals the hardware to the door, eliminating hidden air gaps.
Available in letter and magazine sizes. Finished in Satin Brass, Satin Nickel, and Satin Black. All visible components including screws and hinge pins finished to match.
Brass-Seal™ / Interior Forged Brass Mail Slot (Calibrated)
Calibrated
From Within.
Solid forged brass face plate. A calibrated closure mechanism is designed to allow mail to pass easily while returning to a precise, sealed position after each delivery. A continuous perimeter gasket seals the hardware to the door face on the interior, completing the seal across the full thickness of the door. Independently tested under ASTM E283.
Specified independently or paired with the Exterior Forged Brass Mail Slot as the complete Brass-Seal™ system.
Brass-Seal™ / Forged Brass Mail Slot System
Brass-Seal™ System
Solid Brass.
No Compromise.
Not plated. Not cast. Forged brass throughout. Forging compresses the grain structure of the brass, producing a material that is denser, stronger, and more resistant to wear and corrosion.
- Finish PVD: Satin Brass, Satin Nickel, Satin Black. All components finished to match.
- Cavity Gasket Acoustic-lined; absorbs impact, softens exterior noise transmission
- Perimeter Gasket Continuous; seals hardware to door face, eliminates hidden air gaps
Starting at $315 · Use the Product Selector on the homepage
Before You Install
See exactly how the system will mount prior to installation. A full-scale drill template lets you visualize placement on your door before committing to a single hole.
Order Drill Template → Free, ships in 2-3 business days01
Forged Brass Construction
Solid forged brass throughout. Not plated, not cast. A material choice that communicates permanence and rewards close attention over years of use.
02
Verified Air Infiltration Control
The mail slot is one of the most overlooked openings in a door. The Brass-Seal™ system is engineered to close it, and independently tested by Intertek to prove it.
03
Verified Performance
Air-sealing performance that's independently tested and proven. Visit the Testing Authority section to learn more.
04
Architect Specified
Designed to meet the demands of high-end residential and commercial applications. Specification documentation and material samples available on request.
05
Finish Integrity
PVD (Physical Vapor Deposition) bonded to solid forged brass at molecular level. Not a surface coating. Available in letter and magazine sizes. Finished in Satin Brass, Satin Nickel, and Satin Black. All visible components including screws and hinge pins finished to match.
06
Sound Attenuation
An acoustic-lined cavity gasket is featured in both the Exterior and Interior Forged Brass Mail Slots. It absorbs impact and reduces sound transmission in both directions, softening the passage of exterior noise into the home. A continuous perimeter gasket eliminates hidden air gaps at the hardware-to-door interface.
A Testing Standard
Setting the Mail Slot
Testing Standard.
Among the first mail slot systems to carry independent ASTM E283 verification, placing it in the same performance category as tested windows, doors, and curtain wall components.
Tested Performance.
Not a Promise.
Most mail slots are never tested. The Brass-Seal™ system is.
Independent testing under ASTM E283, the recognized standard for air infiltration through doors and windows, confirms the Brass-Seal™ system reduces unwanted air movement through the mail slot opening to a measured, verified result.
0.6 L/s/m² (0.12 cfm/ft²) at 75 Pa (~25 mph wind pressure) — 60% below the allowable maximum.
1.0 L/s/m² (0.20 cfm/ft²) at 75 Pa (~25 mph wind pressure) — 33% below the allowable maximum.
1.0 L/s/m² (0.20 cfm/ft²) at 75 Pa (~25 mph wind pressure) — 33% below the allowable maximum. In a paired system, the exterior unit is the limiting layer under pressure. Each unit retains its independent sealing function.
That result holds year-round. The Brass-Seal™ system is a permanent hardware installation, not a seasonal fix.
Testing StandardASTM E283
Testing AuthorityIntertek
Report No. T4376.01-301-44-R1
Available on request for specification review.
What the Results Mean
Under pressure testing, the exterior slot is the primary limiting layer. The interior slot performs to a tighter result when tested independently. Both are verified by Intertek.
Two units. One system. Independently tested. The entrance performs at the level the door demands.
Patent Status
Pending
The Brass-Seal™ system is patent pending. Proprietary sealing engineering developed exclusively by BOTA for this application.
Door-Level Performance.
Mail Slot Opening.
Tested. Proven. The opening performs as if it were never there.
| Product | Brass-Seal™ Forged Brass Mail Slot |
| Material | Solid Forged Brass |
| Patent Status | Patent Pending Brass-Seal™ |
| Testing Standard | ASTM E283 / Air Infiltration |
| Testing Authority | Intertek |
| Sizes | Letter and Magazine |
| Finish Options | PVD: Satin Brass, Satin Nickel, Satin Black |
| Cavity Gasket | Acoustic-lined; absorbs impact, softens exterior noise transmission |
| Perimeter Gasket | Continuous; seals hardware to door face, eliminates hidden air gaps |
| Application | Residential and commercial |
| Spec Documents | Available on request |
| Lead Time | Available on inquiry |
Specify With Confidence.
Specification documentation, material samples, and press assets available for architects, designers, and editors.
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