Laowu 4x4 Metal Electrical Box Cover Plate, 4 Pcs Electric Junction Box Panel, 4 Inch Galvanized Steel Metal Corrosive Resistant Cover For Electrical Boxes

Why I keep a pack of these on hand

I keep a small stash of 4-inch square box covers in my electrical drawer, and the Laowu cover has earned a permanent spot in that pile. It’s a simple piece of hardware—galvanized steel, blank face, two fasteners—but the details matter: fit, finish, rigidity, and how forgiving it is when your box isn’t perfectly aligned. After installing the full four-pack across a few basement and garage projects, here’s how these covers performed.

Build quality and finish

The steel is thicker than the bargain-bin plates I’ve used, with enough rigidity that it doesn’t oil-can when you tighten the screws. That extra stiffness keeps the face from dimpling and helps it sit flat against the box and drywall. The galvanized finish is even and clean, with no blotches or streaks, and the edges are properly deburred—no burrs to snag gloves or scratch paint.

As a blank plate, the face is unbranded and uncluttered. In exposed locations (mechanical room, garage), it looks tidy on its own without a decorative plastic cover. It won’t pass for architectural hardware, but for utility spaces it’s more than presentable.

The galvanization will shrug off humidity and the occasional splash. I’d use it confidently in a basement, laundry room, or garage. It’s worth stating the obvious: this is not a weatherproof, gasketed cover. If you’re sealing an outdoor box, reach for a listed weatherproof blank with a gasket and matching box.

Hardware and slot design

Each plate uses two fasteners on opposing corners, as you’d expect for a 4-inch square (1900) box. The plate I used has one round hole and one elongated keyhole slot. Practically speaking, that means you fully remove one screw and partially back out the other; you hang the plate on the slot, swing it into place, and then install the second screw. I like this arrangement for service work—you can pivot the cover open later without it falling off—but if you prefer slots on both sides for tool-free removal, note this design choice.

The slot gives you a bit of play to compensate for boxes that aren’t perfectly square to the wall. Don’t expect miracles—it’s not going to make up for major misplacement—but it’s enough to true up the plate so it sits parallel with adjacent finishes. On two slightly twisted boxes in my garage, I was able to get the face visually square without stressing the screws.

My pack included machine screws. If yours doesn’t, any standard 8-32 machine screw will do. I’d suggest sticking with pan-head or truss-head for better bearing on the slot.

Installation experience

Installation is as straightforward as it gets:

• Kill power and verify with a tester.
• Tuck and secure conductors in the box so the plate won’t pinch insulation.
• Start one screw into the box, back it out a turn or two, hang the plate on the keyhole slot, swing it closed, and install the second screw.
• Snug both screws evenly—tight enough to seat the plate, not so tight that you deform it.

On drywall, the square edge of the plate covered minor tears from the knockout and a slightly overcut opening around one box. If your opening is oversized, this plate has enough face area to hide small mistakes. If your conductors or wirenuts are riding high, consider a raised cover instead; this is a flat blank and doesn’t provide extra volume.

The plates aligned cleanly with both older steel 4-inch boxes and a newer nonmetallic variant I had on hand. No cross-threading, no fighting the corners, and no rattling after tightening.

Fit and compatibility

• Size: 4-in square, standard for 1900 boxes and many junctions.
• Pattern: Opposing-corner fasteners, one round hole and one slotted/angled hole.
• Clearance: Flat profile; best for junctions with room to tuck wires behind the plane of the box.
• Aesthetics: Plain galvanized face, consistent sheen, no stamped logos.

These covers are ideal for closing off unused boxes, protecting splices in accessible junctions, and tidying up temporary cut-ins after you remove a device. They’re especially suited to unfinished spaces where a clean metal face is acceptable.

Durability and safety considerations

Galvanized steel is inherently flame-resistant and holds up to heat far better than plastic blanks. In practice, the plate stays cool and doesn’t flex under typical use. The finish handled a couple of scuffs from my nut driver without bright scratches showing through, which tells me the zinc layer isn’t paper-thin.

A couple of safety notes I follow:

• Keep conductors clear of the screw paths; a nicked insulation from a wandering screw is a failure waiting to happen.
• If you’re using metal boxes, make sure the box is properly bonded per code. The cover itself doesn’t need a separate bond—the screws tie it to the box—but the box needs to be grounded.
• Do not bury junctions. This is a great plate for accessible splices; it is not a license to hide a box behind drywall.

Where it excels

• Small commercial build-outs and garage/basement projects where utility-grade appearance is fine.
• Quick closures for cut-in boxes after device removal.
• Situations with slightly misaligned boxes; the slotted hole offers just enough adjustment to square the face.
• Damp-ish indoor environments where corrosion resistance matters.

What could be better

• Slot on both sides: I’d prefer elongated slots on both corners for easier blind installation in tight spaces. The single-slot design is service-friendly but requires fully removing one screw.
• Gasket option: Including a thin foam gasket would help decouple the plate from uneven surfaces and reduce any minor buzz in vibration-prone locations. Not essential, but nice.
• Raised alternative: A companion raised blank would address shallow boxes packed with splices; as-is, this flat plate assumes adequate depth.

Practical tips

• If you’re covering an overcut drywall hole, run a light bead of paintable caulk around the perimeter after installation for a finished look and to keep dust out.
• For boxes set proud of the wall, use nylon spacers behind the screws to avoid bowing the plate.
• Label the inside of the plate with a Sharpie before installing—circuit numbers, date, or a quick note. The next person working on it (possibly you) will appreciate it.

Longevity after a few weeks

Between a laundry-room junction and two garage boxes, the plates still sit flat and haven’t loosened. No rust blooms, even on a wall that occasionally gets condensation. The screws haven’t backed out, and the faces haven’t picked up fingerprints the way some cheap zinc plates do. In short, they’re doing what a good cover should do—disappear from your mind once they’re installed.

The bottom line

The Laowu cover gets the fundamentals right: solid steel, clean galvanization, true corners, and a forgiving slot that makes up for minor box misalignment. It’s not showy, and it doesn’t try to be. For indoor and semi-damp utility spaces, it’s exactly what I want from a blank plate—sturdy, tidy, and uneventful.

Recommendation: I recommend this cover for anyone who needs a reliable 4-inch square blank for junction and electrical boxes in indoor or sheltered locations. The build quality, finish, and fit are a cut above the flimsy plates you’ll encounter at the lowest price points, and the four-pack is practical to keep on hand. Just be aware of the single-slot layout and the flat profile; if you need a weatherproof exterior solution or extra internal clearance, choose a gasketed or raised alternative. For typical basement, garage, and utility-room work, this one’s an easy yes.