Package Master Locking Post-Mount Mailbox - Extra Large, Galvanized Steel, Mail Boss

Mail Boss Package Master locking post-mount mailbox overview

The Mail Boss Package Master is a USPS-approved extra-large secure mailbox designed for homeowners who regularly receive small parcels, prescriptions, and high volumes of mail. With a 3,118.5 cu. in. capacity, this residential locking mailbox accommodates letters, magazines, and small packages without requiring a signature. The T1 mailbox style mounts on a standard post, making it a direct upgrade for any curbside mailbox installation. It is approved by the U.S. Postmaster General and backed by a Limited Lifetime Warranty.

Galvanized steel construction and powder coat finish

The Package Master is built from welded 12- and 14-gauge electro-galvanized steel, giving it the structural rigidity needed to resist impact and vandalism at the curb. A powder coat finish protects the exterior against UV exposure, moisture, and corrosion, extending the service life of this outdoor mailbox in all climates. Stainless steel hinges are used throughout to prevent rust and ensure smooth, long-lasting door operation. The combined material choices make this metal mailbox suitable for year-round residential use without requiring significant maintenance.

High-security locking system and Mail Shield anti-fishing technology

The Package Master's patented anti-pry latch uses a chrome-alloy tempered steel hook cam that locks the door firmly against forced entry attempts. The locking access door is secured by a commercial-grade high-security 12-disc wafer lock engineered to deter drilling and picking. Mail Shield technology — patented and unique to Mail Boss — physically blocks the mail slot opening to prevent fishing tools from retrieving mail or packages once deposited. Three laser-cut keys are included, and the mailbox also features an outgoing mail slot with indicator flag and a hopper-style package drop door that is leak-protected and snow-plow resistant.

Post-mount installation dimensions and compatibility

The Package Master installs using the patented Fast-Trak Mounting Plate, which is included in the box and eliminates the need for complex alignment during setup — no assembly is required beyond attaching the unit to the post. The mailbox is compatible with Mail Boss posts, an existing 4x4 mailbox post, or a gang plank for multi-unit configurations. Assembled dimensions are 16 in. H × 12 in. W × 21.5 in. D, giving carriers easy access while keeping the footprint manageable on a standard residential post. All mounting hardware, reflective house numbers, and a vandal-resistant flag are included to complete the installation.