Mail Slot
Insulator
Block Out The Air
Interior. Discreet. Immediate. An interior solution built to work within the door.
BOTA Mail Slot Insulator
Magazine Size / Exterior Side
London Design Awards, Gold 2024
London Design Awards
Gold 2024 / Product Design
Patents
Two Granted Utility Patents
The most overlooked opening in the door.
Finally addressed from within.
The BOTA Mail Slot Insulator is positioned within the existing mail slot cutout without modification to the door. It reduces air infiltration, reduces sound transmission, and places a protective barrier between the interior of the home and the outside world. No tools. No modification. Immediate results.
The Mail Slot Insulator fits rectangular cutouts only. If your cutout is oval, your flap opens inward, or your opening is too narrow, see the Brass-Seal System.
Mail Slot Insulator / Letter Size / Interior Side
Precision
from Within.
The interior side of the BOTA Mail Slot Insulator shows the acoustic flap, the steel closure bar, and the magnetic base in their working relationship. The steel bar attracts to the magnets at the base of the unit to maintain a secure, repeatable closure after each delivery.
The acoustic flap conforms to the exact shape of the cutout over several hours after installation. After that, it performs identically every time.
- SizeLetter
- PatentsTwo granted utility patents London Design Awards Gold
- ClosureSteel bar / magnetic base
- InstallationTool-free, no door modification
Mail Slot Insulator / Installed / Exterior Side
Discreet.
By Design.
Installed from the interior, the BOTA Mail Slot Insulator is invisible from the exterior of the door. It works entirely within the existing mail slot cutout. No alteration to the exterior hardware. No visible change to the face of the door.
Compatible with virtually all existing mail slot designs. Available in letter and magazine sizes. Pairs with the Brass-Seal™ Exterior Forged Brass Mail Slot for the most complete entry upgrade.
Pairs with the Brass-Seal™ exterior for a complete, independently tested system.
- VisibilityNot visible from exterior
- SizesLetter and magazine
- CompatibilityWorks with virtually all existing mail slot designs
- PerformanceAir infiltration reduction, sound reduction
Mail Slot Insulator / Installed / Interior Side
Safe on
Both Sides.
The steel closure bar places a physical barrier between the mail carrier and pets on the interior of the home. Mail passes through freely. Hands are better protected.
The acoustic flap absorbs impact and reduces sound transmission in both directions, softening the passage of exterior noise into the home.
- Steel BarMagnetic closure / physical safety barrier
- Acoustic FlapAbsorbs impact, reduces sound transmission
- SafetyBarrier between mail carrier and interior
- After InstallationFlap conforms to cutout over several hours. This is normal.
01
First in Category
The BOTA Mail Slot Insulator is the first in its category to expand both horizontally and vertically, accommodating virtually all existing mail slot cutout sizes without modification to the door. Available in letter and magazine sizes.
02
Tool-Free Installation
No tools. No fasteners. No modification to the door. Adhesive-backed perimeter foam is first installed into the mail slot cutout. The insulator is then placed into the opening and clicked apart, expanding horizontally then vertically until firm against the foam. The flap conforms to the exact shape of the opening over several hours after installation.
03
Safe by Design
The steel closure bar places a physical barrier between the mail carrier and the interior of the home. Mail passes through freely. It also attracts to the magnetic base for a secure, repeatable closure after each delivery.
04
Sound Reduction
The acoustic flap absorbs impact and reduces the transmission of exterior noise.
05
Award Winning
London Design Awards, Gold 2024. Recognized for innovation, precision engineering, and design excellence. Two granted utility patents. The BOTA Mail Slot Insulator is a category-defining product.
06
Historic Properties
Designed as a retrofit solution, the Mail Slot Insulator can be added without replacing or altering the existing exterior mail slot. Properties of historic origin or clients who wish to retain an exterior mail slot can add the Insulator without replacement.
Supports the Energy
Efficiency of the Home.
Even small openings in a door can allow conditioned air to escape and outdoor air to enter. By limiting the flow of air through the existing mail slot opening, the BOTA Mail Slot Insulator supports the energy efficiency of the home while offering an easy, tool-free installation.
- Helps keep conditioned air inside
- Reduces cold and hot drafts
- Improves comfort instantly
- Supports overall home energy efficiency
- Reduces sound transmission in both directions
Starting at $119 · Use the Product Selector on the homepage
Installs in
minutes.
No tools required.
No modification to the door. No hardware. The adjustable frame sets the fit. The insulator does the rest.
Watch the installation video →
Questions about installation?
We are here to help.
- 01 Interior plate removal (if needed). If the interior mail slot plate blocks access to the door cutout, remove it and set it aside for reinstallation.
- 02 Install the adhesive-backed perimeter foam into the existing mail slot cutout. Foam is supplied long to fit a range of sizes. Trim excess only after installation is complete.
- 03 Remove the Velcro-backed closure bar and set aside. Place the insulator into the mail slot opening in its unexpanded state. Expand horizontally then vertically until firm against the perimeter foam with no movement and no air gap.
- 04 Install the C-Clip. Select the clip that matches the opening created during expansion and snap it into place to secure the width.
- 05 Final assembly and check. Attach the Velcro-backed closure bar to the bottom edge of the flap so the steel rod engages with the magnet. Confirm the flap opens freely and closes fully with no air gaps.
Pair With the
Brass-Seal™ System.
The BOTA Mail Slot Insulator works from within. The Brass-Seal™ Forged Brass Mail Slot addresses the entry from the door surface. Each stands alone. Together, two solutions. One opening. Nothing left unaddressed.
View Brass-Seal™ →Interior. Discreet. Immediate.
Tool-free installation. Immediate results. Two granted utility patents. London Design Awards Gold 2024.
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