375 pc. box (approx). Use with steel studs and track. Phillips #2 drive, metal to metal fastening 16 to 20 ga. This self-drilling screw is used in wood, fiberglass, and metal, and it possess a drill point enabling it to drill its own hole in thin gauge steel. The sharp threads create their own mating thread when drilled into the material. No pre-drilled pilot holes are necessary.