us postal drop box

Most smaller drop boxes are made from heavy‑duty steel with rust‑resistant powder coatings. Parcel boxes often use galvanized steel, and some larger or premium units combine materials such as cast aluminum with galvanized steel for added durability.

Manufacturers use several features to keep contents dry: a rainproof delivery shield or flap over the slot, built‑in drainage holes and rubber pads at the bottom to remove water, and rust‑resistant powder‑coated finishes to prevent corrosion.

Through‑wall units install with adjustable slides or sleeves and are specified for walls roughly 2.8–7.9 inches (70–200 mm) thick. Door‑mounted boxes are described for doors around 1.7 inches (43 mm) thick and typically include the mounting hardware and installation instructions.

Larger parcel boxes publish specific interior capacities—an example is 16.54 × 14.76 × 20.28 inches. Rotating‑drum designs list maximum parcel sizes too; one such design accepts parcels up to about 11.5 × 7.3 × 9.3 inches.

Typical anti‑theft protections include interior metal baffles and embedded anti‑theft plates that block hands from reaching inside. Additional measures noted include magnetic or baffle door designs and extra security plates on parcel boxes to reduce fishing and unauthorized access.