Metallics QCSH10B Anchor 1/4 x 1-1/4 (5/16" Hd) Quadrive Concrete Screw USA (1000pcs)

The QCSH10B is a 1/4 inch diameter concrete screw, and 1/4 inch concrete screws are installed in a 3/16 inch hole drilled with a carbide bit. Drill the hole deeper than the screw will penetrate so dust has somewhere to go. At 1-1/4 inches overall length, the usable embedment is shallow, so this size is meant for thin fixtures bolted tight to concrete, block, or brick rather than thick standoffs.

Yes, that is the normal use for it. A 1/4 x 1-1/4 concrete screw holds one-hole and two-hole straps, device boxes, and small brackets directly against concrete or block with no plug or shield, and the 5/16 inch hex head lets you run it with an impact driver. Keep in mind the 1-1/4 inch length is consumed partly by the thickness of whatever you are fastening, so for anything thicker than a strap or a thin plate, step up to a longer screw.

It drives with a 5/16 inch hex socket or nut setter on an impact driver. The Quadrive head on the QCSH10B is a hex washer head, so you seat it with a socket rather than a bit, which keeps the fastener from camming out when you are running hundreds of them.

Order it as Metallics QCSH10B. That covers the 1/4 x 1-1/4 inch Quadrive concrete screw with the 5/16 inch head, US made, in the 1000 piece pack.

One thousand pieces per box. That is a contractor bulk pack, sized for repetitive work like strapping conduit, mounting panel backing, or fastening track and furring to concrete, where you are setting the same 1/4 x 1-1/4 anchor over and over.

It backs out with the same 5/16 inch socket, which is why these are used for temporary bracing and for fixtures that get serviced. Reusing the same hole is not good practice though, since the screw cuts its own thread in the masonry and a second install into worn threads gives you much less hold. Move over and drill a fresh hole.