Cheaply that is! I desperately need 20mm glass lenses but DX etc. don't carry them. I don't want to pay big amounts for my lenses when the entire light cost me 10 bucks.
Can anybody think of any way to cleanly DIY a bigger diameter lens into a smaller? Or someone else need some sizes that are not cheaply available? Maybe we could ask Jim@MF to sell some...
HK is probably the best bet. There is always the expensive http://www.flashlightlens.com
You can try http://www.flashlightlens.com/str/index.php
They're closed until June 28th (and their website seems borked), but they do carry UCL (not borofloat) lenses in 20mm.
at $4 + shipping, you might be better off getting a cheap new host, though
Edit: D'oh, Don beat me to the punch