Eruinfang Padlock Hasp 4 Inch Door Hasp Latch Lock Stainless Steel Padlock Clasp Black Hasp Lock Gate Hasp with Fixing Screw for External Doors Window Cabinet Pet Cage

What I tested and why

I put the Eruinfang 4-inch hasp to work on two jobs that see real-world abuse: an outdoor resin shed that lives in full sun and rain, and a steel trailer toolbox that rattles down rough roads. I wanted something compact, corrosion-resistant, and simple enough to install with basic tools. This model’s stainless steel construction, black finish, and concealed-fixing design made it a good candidate for light-to-medium security where a padlock completes the system.

Design and build quality

At 4 inches long and about 1.5 inches wide, this is a compact, low-profile hasp that doesn’t look out of place on small shed doors, cabinets, or gates. The main leaf sits flush and swings cleanly; the hinge action is smooth with no gritty feel or binding out of the box. The finish is an even satin black—more subdued than glossy—and it blends well on dark surfaces while looking intentional on lighter ones.

The body is stainless steel, which matters if you’re mounting outdoors or in damp spaces. After several weeks outside—including a couple of hard rains—the finish hasn’t lifted and I’m not seeing the telltale rust bloom around screw heads or the hinge knuckle that cheaper zinc parts develop. The staple (the loop the padlock passes through) is advertised as hardened, and it does feel tougher than the leaf metal; a file skates a bit more on it than on the body. That’s what you want—if a thief goes after anything, it’s usually the staple.

This is not a heavy, armored security hasp. The leaf gauge is respectable for its size, but it’s a pragmatic, light-to-mid-duty part—appropriate for sheds, lockers, cabinets, and pet enclosures. On the trailer toolbox, it tightened up the lid nicely without adding bulk that snags cargo or clothing.

Installation experience

Installation is straightforward: position the leaf so the hinge throws freely, align the staple plate, mark your holes, and drive the included screws. A few tips from my installs:

• Pre-drill pilot holes, especially in hardwoods or composite doors. A 1/16 to 3/32 inch bit was about right for the included screws.
• Test the swing before committing. Close the hasp over the staple to confirm the padlock clears the edge of your door and frame.
• If you’re mounting to thin sheet metal (like a toolbox), consider backing washers or through-bolting the staple plate for extra bite.
• Set your driver to a low clutch setting. Small exterior screws can twist off if you power through.

The concealed-fixing design is handled well on the main leaf. Once closed, the leaf hides its own screw heads, which gives you a meaningful bump in tamper resistance. The staple plate screws remain exposed—as is typical on this style—so if you need more than “keep honest people honest,” upgrade those to security screws or through-bolt with nylock nuts on the back side.

My only minor gripe: you get just enough screws for the install with no extras. If you drop one in the grass or strip a head, you’ll be rummaging through your hardware bin. It’s not a deal-breaker, but I’d love a spare or two in the pouch.

Security in practice

A hasp is only as strong as its weakest link: the leaf, the staple, the fasteners, the door material, and your padlock all share the load. In my use, this model provides:

• Decent resistance to casual prying. The leaf overlaps cleanly and sits flush, which reduces easy pry purchase, but it’s not a shrouded or “anti-pry cup” design.
• A hardened staple that discourages quick hacksaw attempts. Pairing it with a hardened, weatherproof padlock with a shackle that fits snugly through the staple closes the loop.
• Better tamper resistance via concealed leaf screws. That alone stops the most trivial “unscrew it” approach.

If you need true high security for an expensive tool chest or a remote gate, you’re better off with a heavier, shrouded hasp and a closed-shackle padlock. For sheds, cabinets, and utility boxes, this is a sensible balance of size, strength, and price.

Padlock fit: I tested with a couple of common outdoor padlocks. Standard 1.75 to 2-inch laminated and brass-body padlocks with medium shackles fit without fuss. Aim for a shackle diameter that fills the staple as much as possible while still moving freely; slop equals leverage for prying.

Weather performance

Outdoor hardware lives or dies by materials and coating. Stainless steel is the right call here. The black finish hasn’t chalked or chipped, and the hinge hasn’t collected red rust at the pin—both good signs. If you live right on the coast or you’re bolting this to a boat hatch, you may still want marine-grade 316 stainless hardware and a marine lock, but for typical backyards and garages, this held up as expected.

I’d recommend a dab of exterior sealant under the screw heads on wood siding or doors to keep water out of the pilot holes, and a tiny drop of dry lube on the hinge if you live in a dusty area. Otherwise, it’s largely install-and-forget.

Fit and finish details

• The edges are lightly eased, so you won’t catch a sleeve on a burr.
• The knuckle is compact, which keeps the profile low and avoids snag points.
• The black hardware matches the hasp, which helps the install look intentional rather than patched together.

Dimensionally, it suits small and mid-size doors or lids. If you’re locking something large or subject to heavy force, you’ll want a longer hasp to spread load across more fasteners.

Where it works best

• Outdoor resin or wooden sheds
• Garage cabinets and tool chests
• Trailer and truck-bed toolboxes
• Lockers, gates, and pet enclosures
• Windows or doors where a compact latch is needed without a bulky look

In each of those cases, the balance of corrosion resistance, clean looks, and easy installation makes it a natural pick.

What I’d improve

• Include a couple of spare screws. Small hardware gets lost, and having backups saves a trip to the store.
• Offer a through-bolt kit as an option. Many users mount to thin sheet metal; washers, nuts, and security torx bolts would elevate the package.
• A slightly thicker leaf variant would be a welcome “pro” option for higher-risk installs without jumping to a much larger footprint.

None of these are deal-breakers, and at this price point the choices make sense. But they’re opportunities to nudge the product closer to a “fits all cases” solution.

Practical installation checklist

• Choose your padlock first and verify the shackle fits the staple snugly.
• Mark and pre-drill pilot holes; avoid splitting and stripped screws.
• Confirm hinge swing and padlock clearance before driving all screws.
• For metal boxes, use washers or through-bolt the staple if possible.
• If you need added tamper resistance, swap the visible staple screws for security-head screws.

Following that routine, both of my installs went on in minutes and have stayed tight with no rattles.

The bottom line

The Eruinfang 4-inch hasp hits the right notes for everyday security: stainless construction, a tidy black finish, concealed fixings where they matter, and no-nonsense installation. It’s not a brute-force, high-security hasp—and it doesn’t pretend to be—but for securing sheds, cabinets, and utility boxes against casual access and the elements, it performs reliably.

Recommendation: I recommend this hasp for light-to-medium duty applications where you want clean looks, corrosion resistance, and quick installation at a fair price. Pair it with a quality weatherproof padlock and, if needed, upgraded fasteners on the staple plate, and you’ll have a tidy, dependable solution that’s easy to live with. If your use case involves high-value contents or frequent attempted tampering, step up to a heavier, shrouded hasp—but for most homeowners and DIYers, this one’s an easy win.