Cage nut

A cage nut or caged nut consists of a nut in a spring steel cage which wraps around the nut. The cage has two wings that when compressed allow the cage to be inserted into the square holes, for example, in the mounting rails of equipment racks. When the wings are released, they hold the nut in position behind the hole. Cage nuts conforming to this description were patented in 1952 and 1953. The original design requires an insertion tool to install a cage nut into a hole. Newer designs featuring squeeze-and-release tabs allow for tool-less installation.

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