10-32 cage nuts can be used in equipment racks that have “Universal Rails.” These are the rails that have square holes punched in them, (rather than the style that has a tapped hole drilled directly in the rail). Cage nuts merely snap into one of these square holes creating a replaceable, threaded mounting hole for a 10-32 screw.
Using cage nuts also gives you the ability to choose different thread sizes within the same installation. This is an important point when mounting a variety of equipment from UPS devices to small network switches.