Metallics TEK10M Screws 14 x 1 HWH 3/8Hd TS D-Pt3 St-Z (1000 pcs)

It's zinc plated steel, which is a dry indoor and protected finish. Zinc plating handles incidental moisture but it is not a marine or sustained exterior coating, so for rooftop conduit supports, wet locations, or coastal work you want stainless or a coated exterior fastener instead. Inside a building, in panel rooms, on strut runs, and on interior metal framing it is the standard choice.

Only if the combined thickness of what you are fastening plus the base steel leaves room for the thread to fully engage past the drill point. The TEK10M gives you 1 inch of total length, so it suits a strap, clip, or bracket landing directly on steel framing or strut. Stacking a spacer, a thick plate, or fastening through insulation or sheathing eats that length fast, and you should step up to a longer self-driller rather than relying on partial engagement.

One thousand pieces per box. That is a bulk contractor pack, sized for crews hanging strut, conduit straps, enclosures, and metal stud work rather than a one-off repair, so a single box typically covers a full fit-out rather than a service call.