Made of alloy steel, these low-profile screws are nearly twice as strong as their stainless steel counterparts. With half the height of a standard socket head, these low-profile screws fit in tight spaces, but are weaker than standard socket heads. Length is measured from under the head.

Black-oxide steel screws are mildly corrosion resistant in dry environments. Zinc-plated steel screws have a zinc outer layer that protects the steel under it from rust, extending the life of the screw.

Class 8.8 steel screws are medium-strength, so they’re strong enough for use with most machinery and equipment. Coarse threads are the industry standard; choose these screws if you don’t know the pitch or threads per inch. DIN screws meet international standards for materials and dimensions.

Tighten DIN 6912 screws with DIN 6911 L-keys—these screws have a recess that matches the extended tip of those L-keys. DIN 6911 L-keys grip these screws snugly so you can install them in difficult-to-reach areas with just one hand. You can also install DIN 6912 screws with standard L-keys, but they won’t grip the screws as securely.