UF 502B battery extension?

Has anyone ever seen an extension tube compatible with the Ultrafire 502B? Of any length?

It’s not so much voltage which I’m trying to mod, rather the physical length of the light…

ah, I see now that there are the 502c and 502d models, that explains it
was hoping to do some colour lego so might see if the body ends can’t somehow be rethreaded together