Metallics TTS31B 10 x 2 in. Pan Head Tri-Drive Tapping Screws - Steel Zinc - Each

The TTS31B takes three different drivers off the same pan head: a slot, a Phillips bit, or a square (Robertson) bit. That is what tri-drive means here, and it is why these are common on service work where the crew is carrying whatever bit is already in the gun.

It is a #10 diameter screw, 2 inches long, with a pan head. The 2 inch length is on the long side for a sheet metal screw, so it suits fastening through strut, box flanges, or wood blocking rather than thin sheet-to-sheet work.

These are zinc plated steel. Zinc plating handles indoor and dry or occasionally damp conditions, but it is not a stainless or hot-dip coating, so for sustained exterior exposure, wet locations, or corrosive environments pick a stainless or galvanized fastener instead.

It is a tapping screw, so it cuts its own thread into a pre-drilled or punched hole rather than drilling the hole for you. In sheet metal and light gauge steel you still want a pilot hole sized for a #10; it is not a self-drilling point.

A pan head sits proud on the surface with a flat bearing face and no countersink needed, which is why it is the default for electrical boxes, covers, and strut where the material is too thin to countersink. If you need the head flush with the surface, use a flat head in a countersunk hole; if you want more clamping area on sheet metal, a hex washer head spreads the load wider.

Yes, the TTS31B tri-drive tapping screws are made in the USA, which matters on public and federally funded jobs carrying domestic sourcing requirements.