Construction & Key Features
Our mail drop slots are built from 1/4″ thick aluminum plate and 20-gauge steel — heavy-duty construction designed for long-term daily use in residential and commercial doors and walls. Key specifications and features:
- Through-wall chute design: Angled 5¾” deep mailbox chute directs mail through the wall or door and deposits it on the interior side.
- Spring-loaded mail flap: Adjustable mail flap stop keeps the flap securely closed between deliveries.
- No postal lock required: Mail drop slots do not require a USPS lock — suitable for US mail delivery, payment drops, rent check drop-off, and intra-office mail.
- Engravable front flap: Front flap ships blank; optional engraving available at additional cost.
- Finishes: Aluminum, Brass, Green, Sandstone, and Bronze powder coat.
- Optional collection receptacle: Aligns with the mailbox chute on the interior wall side for secure mail storage — sold separately.
- Use alone or with receptacle: Mail slot can be installed independently or combined with the matching Collection Box Receptacle.
Mail Slot Through Wall: Door vs. Wall Installation Options
Mail drop slots can be installed through a door or through a wall — both configurations use the same through-wall chute design but require different installation approaches:
- Door mail slot — The most common residential installation. The slot is mounted directly through the front door of a home, apartment, or office, allowing the postal carrier to deliver mail through the door without opening it. Door mail slots require a door thickness compatible with the chute depth (5¾” standard). Ideal for single-family homes and apartments where a traditional mailbox at the curb or door is not preferred.
- Mailbox slot in wall — The slot is installed through an exterior wall rather than a door, typically in commercial buildings, office lobbies, and multi-family residential properties. Wall installation allows the mail slot to be positioned at any height on any exterior wall surface. Requires cutting a precise opening in the wall matching the slot’s rough-in dimensions.
- Insulated mail slot — For both door and wall installations in cold climates, an insulated mail slot adds a weatherproof seal or insulating flap to the interior side of the slot to prevent drafts, moisture, and cold air from entering through the mail opening. Particularly important for exterior wall installations where the slot creates a direct pathway through the building envelope.
Adding a Mail Receptacle to Your Mail Slot
A mail receptacle — also called a collection box receptacle — is an optional interior-mounted box that attaches to the inside of your wall or door, aligning with the mailbox chute to catch and store mail as it is delivered through the slot. Without a receptacle, mail falls through the chute onto the floor inside the building. With a receptacle, mail is collected in a secure, lockable box that keeps it organized and protected from being kicked around or scattered.
The Collection Box Receptacle from US Mail Supply is designed to pair directly with our mail drop slot, aligning precisely with the chute opening on the interior wall face. Key features of the mail receptacle:
- Secure locking mechanism — Only you can open the receptacle to retrieve mail.
- Ample capacity — Sized to hold multiple days of standard letter mail and flat envelopes.
- Sold separately — Order both the drop slot and receptacle for a complete through-wall mail delivery and collection system.
- Matching finishes — Available in matching finishes to the mail drop slot for a coordinated installation.
For properties where mail security is a priority — offices, commercial buildings, and homes where mail is left unattended for extended periods — combining the mail drop slot with a locking mail receptacle is the recommended setup.
Frequently Asked Questions About Mail Drop Slots & Receptacles
What is a door mail slot?
A door mail slot — also called a mail drop slot or mailbox slot — is a rectangular opening mounted in a front door or exterior wall that allows mail carriers to deliver letters and flat packages directly through the door or wall without opening it. The slot has a spring-loaded flap that opens when mail is pushed through and closes afterward to keep out drafts and weather. Door mail slots are a popular alternative to a curbside mailbox for homes and apartments where through-door delivery is preferred, and are also widely used in commercial office buildings and multi-family residential properties.
What is the difference between a door mail slot and a mailbox slot in a wall?
A door mail slot is installed through a door — the most common residential configuration, where the postal carrier delivers mail through the front door without opening it. A mailbox slot in a wall is installed through an exterior wall rather than a door, used in commercial buildings, office lobbies, and multi-family properties where the slot is positioned on a wall surface rather than a door panel. Both use the same through-wall chute design and can be paired with the same collection box receptacle. The main practical difference is the installation surface — door vs. wall — and the resulting cut dimensions required.
What is an insulated mail slot?
An insulated mail slot is a mail drop slot fitted with an additional weatherproof seal, brush strip, or insulating flap on the interior side of the slot opening. Because a mail slot creates a direct opening through a door or exterior wall, it can allow cold air, drafts, and moisture to enter the building — particularly in cold climates or on north-facing exterior walls. An insulated mail slot minimizes this heat loss by sealing the interior of the chute opening between mail deliveries. If you live in a cold climate or are installing a mailbox slot in an exterior wall rather than an interior-facing door, an insulated mail slot is the better choice.
What is a mail receptacle and do I need one?
A mail receptacle is a lockable interior box that mounts on the inside of your wall or door, aligning with the mail slot chute to catch and securely store mail as it is delivered. Without a receptacle, mail falls through the chute onto the floor inside the building. If you want delivered mail to be kept organized, secure, and protected from being scattered or accessed by others, a locking mail receptacle is strongly recommended. The mail receptacle is sold separately from the mail drop slot — if you want the complete through-wall mail delivery and collection system, order both. Contact our team to confirm the correct receptacle model for your slot.
Can I use a mail drop slot for USPS delivery?
Yes. Mail drop slots from US Mail Supply are suitable for US mail delivery and do not require a USPS postal lock. USPS carriers can deliver standard letter mail through any mail slot with an opening large enough for the mail piece. Mail drop slots are also suitable for other uses including rent check drop-off, payment drops, and intra-office mail distribution. Note that mail drop slots are not USPS-approved for parcel delivery — packages too large for the slot opening cannot be delivered through it.
What is a mailbox chute?
A mailbox chute is the angled internal channel that runs through the wall or door between the exterior mail slot flap and the interior opening (or receptacle). The chute is angled slightly downward so that mail slides through by gravity from the exterior slot opening to the interior collection point. On US Mail Supply mail drop slots, the chute is 5¾” deep and angled to direct mail smoothly through the wall thickness to the interior side. A deeper or thicker wall may require a custom chute extension — contact our team to confirm compatibility with your wall thickness before ordering.
I’m looking for US mail drops near me — where can I find one?
If you are looking for a USPS blue collection box near your location to drop off outgoing mail, use the USPS collection box locator at usps.com — it shows nearby USPS drop-off points by zip code or address. This page is for buyers looking to purchase and install mail drop slots and receptacles in their own home, door, or commercial building. If that is what you need, you are in the right place — browse our mail slot and receptacle collection above or contact our team for help selecting the right model.