Used to mount network and telecom equipment into standard equipment racks. There are two main types of screws. 10-32 screws or 12-24 screws. The 12-24 screws account for most applications in the field today. These particular rack mount screws have an E-Z start shank. This type of shank is void of threads for the first few "rounds" at the bottom. This allows easy insertion of the screw without having to get it "started" first.