Underneath all of the black paint is an orignial A. Jaegers 4.25" aluminum mirror cell. This one is in pretty good shape, except that the tube mounting holes -- see image -- have been enlarged to about 1/4" and no longer have any internal threads. Can be mounted in a tube with nuts and bolts, of course, like the Edmund 4.25" mirror cell.
Comes with the original (way too big) mirror clips, but I'll include some nice, properly sized aluminum clips if you need them.
Asking $16.50, plus a few bucks for postage.