These alloy steel screws are almost twice as strong as ultra-low profile stainless steel screws. In arid conditions, their black-oxide coating offers a moderate level of corrosion protection. They have a head that is roughly one-third the height of a typical socket head in order to fit in the smallest openings, but their low profile weakens the head. For important fastening applications, it is not advised. Under the head, the length is measured.

If you are unsure of the pitch or threads per inch, go with screws with coarse threads, which are the industry norm.