Metallics JSHC516112SS Screw 5/16-18 x 1-1/2 SHCS 18-8 SS (Jar 100)

The material is 18-8 stainless steel, the common austenitic grade (roughly 18 percent chromium, 8 percent nickel) used for general corrosion resistance. It handles outdoor exposure, washdown areas, and damp vaults far better than plain or zinc-plated steel. For direct salt spray or coastal marine service, 316 stainless is the step up.

SHCS means socket head cap screw, so it drives with a hex key (Allen wrench) in the internal socket, not a screwdriver or a wrench on the head. A 5/16-18 socket head cap screw takes a 1/4 inch hex key. The recessed cylindrical head also lets it sit in a counterbored hole flush with the surface.

100 screws per jar. The jar pack is how Metallics ships these for shop and service-truck stock, so an electrician or maintenance tech can keep a single size on hand and scoop out what the job needs.

Yes, that's the usual electrical use for a 5/16-18 x 1-1/2 stainless socket cap screw: bolting into 5/16-18 strut nuts, channel hardware, enclosure brackets and equipment feet. The 1-1/2 inch length gives you enough reach to pass through a bracket plus a spring nut or washer stack. Match the stainless screw with stainless nuts and washers so you aren't mixing metals at the joint.

Austenitic stainless like 18-8 is prone to thread galling, especially in a stainless-to-stainless tapped hole tightened fast. Run it in slowly, and use an anti-seize on the threads for anything you expect to take apart later. It's also softer than an alloy steel socket cap screw, so don't torque it to black-oxide alloy values.

Order it as Metallics JSHC516112SS. The number reads out as Jar, Socket Head Cap, 5/16, 1-1/2 length, stainless steel, which is how Metallics builds its fastener numbers across the line.