Metallics JSHC38114SS Screw 3/8-16 x 1-1/4 SHCS 18-8 SS (Jar 50)

It's a 3/8-16 x 1-1/4 inch socket head cap screw. The 3/8-16 designation means a 3/8 inch nominal diameter with 16 threads per inch, which is the UNC (coarse) pitch for that diameter, so it mates with standard 3/8-16 nuts, weld nuts, and tapped holes. Length is 1-1/4 inches under the head, since socket head cap screws are measured from the underside of the head.

They're 18-8 stainless steel, the common 300 series austenitic grade used for general corrosion resistance. That makes them suitable for damp and outdoor exposure on electrical strut, enclosures, and support hardware. 18-8 is non-magnetic in the annealed condition and holds up far better than plain or zinc-plated steel, though it is not the grade to choose for direct saltwater immersion, where 316 is the usual step up.

Yes, as long as the channel nut or spring nut is 3/8-16. That thread is one of the two standard sizes on steel strut hardware, so a 3/8-16 x 1-1/4 inch screw drops into 3/8-16 channel nuts, beam clamps, and trapeze fittings. Check the stamped thread size on your nuts first, because 1/2-13 strut nuts look similar and will not take a 3/8 screw.

A hex key (Allen wrench), not a screwdriver or a wrench on the head. Socket head cap screws have a cylindrical head with an internal hex socket, which is why electricians use them where there isn't room to swing a wrench. For a 3/8 inch diameter SHCS the socket takes a 5/16 inch hex key.

Fifty screws per jar. Metallics supplies this 3/8-16 x 1-1/4 inch stainless socket head cap screw in jar packaging rather than loose count, which is how MRO stockrooms and service vans usually carry it, one jar to a bin location.

No. The jar contains screws only, 50 of the 3/8-16 x 1-1/4 inch 18-8 stainless socket head cap screws. If you're bolting through rather than into a tapped hole, order 3/8-16 hex nuts and 3/8 inch flat or lock washers separately, and match them in 18-8 stainless so you don't set up galvanic corrosion against the screw.

Socket head wins where clearance is the problem. The head is a plain cylinder driven from inside with a hex key, so it needs no swing room beside the fastener, which matters inside enclosures, behind panels, and in channel runs tight to a deck. A hex head bolt is faster with a socket or impact and easier to grab with a wrench when you have open access. For a 3/8-16 connection in a crowded box, the 1-1/4 inch stainless SHCS is the one to reach for.