What's this electrical thingy?

Checking the loom from my 1971 ST50 6v which came to me in four boxes, there is a rectifier but also a small square metal at another part of the loom with no electrical components within it, my best guess is that is a crude regulator to add resistance and disperse heat to keep the output from the alternator closer to 6v.
Can anyone help?
Thanks.

If it is orange, then probably the original Honda rectifier. However, whatever colour, best guess it will be a rectifier.

Thanks, it is orange / red, I've just come in from the garage and your right it is the original rectifier. The confusion is that another rectifier was connected in elsewhere, problem solved.

Thanks again.