This is a black nylon cross button with zinc-plated steel threaded rod. This is the BPF 184 (female) model.
It is distinguished by its shape with 3 branches or braces.
This 3-spoke steering wheel comes with a cover (not emerging, closed). A lock nut is recommended for this steering wheel when used at the end of a screw.
They are mostly used for tightening or handling on many industrial machines or various assemblies.