Metallics JSRMO44 Screw 1/4-20 x 1-1/2 OV PH MS 18-8 S (Jar 100)

They're 18-8 stainless steel, the common 300 series austenitic stainless used for general corrosion resistance. That makes them suitable for damp and outdoor locations where a plain or zinc plated screw would rust, though 18-8 is not the grade to pick for direct salt water or marine exposure.

No. This is a machine screw, which means a uniform straight thread with a blunt end. It needs a tapped hole or a nut. It will not form its own thread in sheet metal or bite into wood. For an enclosure or strut you drill and tap to 1/4-20, or pair it with a 1/4-20 nut; for untapped sheet metal, use a self tapping sheet metal screw instead.

Each jar holds 100 screws. Metallics packages this 1/4-20 x 1-1/2 stainless machine screw in jar form rather than a loose box, which is how service vans and MRO stockrooms usually want it, so the quantity stays countable on the shelf.

An oval head needs a countersunk hole just like a flat head, but the crown sits slightly above the surface instead of finishing dead flush. Electricians use it on cover plates and trim where a little visible dome is acceptable and the countersink is already there. If you need the head completely flush with the surface, use a flat head instead; if the hole is not countersunk, a pan head is the right call.

Yes, 18-8 stainless screws are routinely used in steel and aluminum electrical enclosures. Keep in mind that stainless against aluminum in a wet location sets up a galvanic pair, so where the assembly stays wet, plan on a nylon or stainless washer and periodic inspection.

It's stocked as an electrical fastener, a 1/4-20 x 1-1/2 oval head Phillips stainless machine screw sold 100 to a jar. It's the kind of line a contractor or MRO buyer standardizes on and reorders by the jar rather than buying by the piece.