Metallics JSHC14114SS Screw 1/4-20 x 1-1/4 SHCS 18-8 SS (Jar 100)

It's a 1/4-20 x 1-1/4 inch socket head cap screw, so 1/4 inch diameter with 20 threads per inch (UNC coarse) and 1-1/4 inch of length under the head. You drive it with a hex key, not a screwdriver, and it tapped-threads into 1/4-20 holes or takes a 1/4-20 nut.

The material is 18-8 stainless steel, the common 300-series austenitic grade used for general corrosion resistance. That makes it suitable for damp interior spaces, outdoor enclosures, and wet-location boxes where a plain steel screw would rust. 18-8 is not the choice for chloride-heavy or marine splash exposure, where 316 stainless is the usual step up.

100 pieces per jar. It ships as a jar pack rather than a loose count or a bulk box, which is the format most electricians keep on the van or on a shelf in the shop for repeat 1/4-20 work.

Yes, 1/4-20 is a standard thread for channel nuts, beam clamps, and threaded inserts, and a socket head cap screw works wherever clearance is tight. The advantage is the smaller head footprint and the hex key drive, which lets you tighten in a recess or close to an obstruction where a wrench on a hex head won't swing. If you need to run a wrench on it or want a washer-face bearing surface, a hex head bolt is the better pick.

No. The jar contains 100 screws only, so order 1/4-20 stainless nuts, flat washers, or lock washers separately if the application needs them. Where you are threading into a tapped hole, an insert, or a channel nut, the screw is all you need.

On a socket head cap screw the 1-1/4 inch is measured from under the head to the tip, so that full length is available for stacking material plus thread engagement. Figure on at least one diameter of engagement, 1/4 inch here, into a tapped hole or nut, which leaves roughly an inch of usable stack. If your material thickness plus nut height runs past that, step up to a longer 1/4-20.

A 3/16 inch hex key is the standard drive for a 1/4-20 inch socket head cap screw. Pick a quality key for stainless, since 18-8 galls and the socket will round out if the key is a sloppy fit.

18-8 stainless against aluminum is a dissimilar metal pairing, so in wet or outdoor service you can get galvanic corrosion at the joint, with the aluminum doing the sacrificing. It's routinely done indoors and in dry locations. For exposed wet installs, isolate with a nylon or neoprene washer, or use anti-seize at the threads. 18-8 also tends to gall when run dry into stainless threads, so lubricate on assembly.