Metallics FSCS3 Anchor 3/16 x 2-1/4 Flat Hd Square Drive Concrete Screw Nail Point USA (100pcs)

It is a square drive (Robertson) flat head, so you drive it with a square bit rather than a Phillips or hex socket. Keep a spare bit on the truck for a 100 piece box; square drive resists cam-out well but concrete screws are hard on bits.

The FSCS3 has a flat head, which seats down into a countersunk or clearance hole and sits closer to flush than a hex washer head. For flat steel like strut, channel, or a backplate, that keeps the fastener from fouling anything mounted over it. If you are fastening something with a plain round clearance hole and no countersink, the head will still bear on the surface rather than fully recess.

Concrete screws in the 3/16 inch diameter are a masonry fastener, set in a pre-drilled hole in poured concrete, concrete block, or brick. What changes between those materials is the holding value, not the installation method: hollow block gives you much less than solid poured concrete, so for a block wall land the screw in the solid web where you can. At 2-1/4 inches of length you have room for a reasonable embedment behind a strap or box.

No. This is a one-piece concrete screw: drill the hole and drive the screw straight into the masonry. There is no sleeve, shield, or expansion anchor to set first, which is the reason electricians reach for these over a plug-and-screw setup when hanging straps and boxes.

The nail point is the sharpened lead tip on this 3/16 x 2-1/4 concrete screw. It helps the screw find and start in the drilled hole, so you can line it up one-handed overhead or in a tight junction box pocket instead of fishing for the hole with a blunt tip.

Each box is 100 pieces of the 3/16 x 2-1/4 flat head square drive concrete screw, model FSCS3. That is a usable count for a day of mounting conduit straps, device boxes, or strut runs on block and poured concrete without re-ordering mid-job.