Metallics TRM104M 1/4-20 x 2 in. Round Head Tri-Drive Machine Screws - Steel Zinc - Each

The TRM104M round head takes a slotted, Phillips, or square driver, which is what tri-drive means. On a panel or box full of mixed hardware you can run it with whatever bit is already in the drill, and a square bit gives the best stick if you're driving one-handed overhead.

Yes. The TRM104M is cut 1/4-20, meaning 1/4 inch diameter at 20 threads per inch, the standard UNC coarse pitch, so it mates with any 1/4-20 tapped hole, nut, or strut channel nut. Usable grip is the 2 inch length minus the thickness of what you're clamping, so plan on the nut engaging near the far end on thin sheet.

Steel with zinc plating is the right call for dry indoor work, damp locations under cover, and interior box and enclosure mounting. It is not a stainless screw. For direct weather exposure, wet locations, or anywhere near chlorides or coastal air, step up to a stainless 1/4-20 machine screw instead, since zinc plating is a sacrificial coating and will eventually rust through at the cut threads.

A machine screw like the TRM104M has no point and cuts no thread of its own, so it needs an existing tapped hole, a nut, or a channel nut behind it. If you're going into bare unthreaded sheet metal with nothing to catch, a self-drilling or self-tapping screw is the right type. For spring nuts in strut, tapped enclosure bosses, and bolted lug and bracket connections, the machine screw is what the hole is cut for.

Round head sits proud on the surface with a domed crown and a flat bearing face, so it does not need a countersunk hole. Flat head is what you want when the fastener has to finish flush with the material. For surface mounting brackets, straps, covers, and plates where a raised head is fine, the round head TRM104M works directly off an untapered hole.

Yes, the TRM104M 1/4-20 x 2 inch round head tri-drive is a US made fastener, which matters on public and institutional jobs carrying domestic sourcing requirements on the spec.