Metallics TP833SOC Screws 1/4-20 x 1 OV Span TR MS 18-8 (100 pcs)

These take a spanner (snake eye) bit, which has two round pins that drop into the two holes in the screw head. A standard Phillips, Torx, or flat blade will not drive it. If you are installing these to keep a cover or enclosure from being opened with common tools, order the matching 1/4 inch spanner bit or spanner screwdriver at the same time, since no driver is included with the 100 piece pack.

They are 18-8 stainless, the common 300 series austenitic grade used for general corrosion resistance. That makes them suitable for exterior and damp interior work such as outdoor junction box covers, washdown areas, and coastal-adjacent installs where a plated carbon steel screw would rust out. For direct salt immersion you would want 316 instead.

It is an oval head. An oval head partly countersinks into a chamfered or countersunk hole and leaves a low rounded crown above the surface, so it is not fully flush like a flat head. Use it where you want a finished look on a cover plate or trim but a flat head would pull through or sit too deep.

Spanner is the pick when the goal is to stop casual tampering with tools people already carry. Nobody has a snake eye bit in a standard driver set, where Torx and hex keys are everywhere. The tradeoff is torque: the two pin holes in a spanner head take far less drive torque than a hex socket, so for high clamp load or frequent removal a socket or pin-in-Torx head holds up better. For cover plates, grilles, and enclosure doors on a 1/4-20 thread, the spanner head is the usual answer.

One hundred screws per pack. For MRO and facility security work that covers a run of panel covers or guard plates in a single order; it is sold as the 100 piece box rather than loose each, so plan quantities in multiples of 100.