[Boatanchors] ID'ing a knob

[Barry Tuttleman]

two quick photos, both a little out of focus, but i prefer to take mine outside and it's a little late for that; anyone ID this knob?

http://nevadabarry.com/images/knob1a.jpg
http://nevadabarry.com/images/knob1b.jpg

dial engraving occupies 50% of the circumference, range from 0 - 100
w/ ten divisions between numbers; the indent on the black portion is
locked to "50"; OD is approximately 2 11/16"; two slot head screws
are the setscrews; nice "heft" to the weight.

any ideas?
TIA!
barry
carson city, nv