Can someone help (re)enlighten me on the difference of the various MR (what's that?) materials. I've tried searching but my admittedly limited computer skills have failed to produce a concise explanation.
The opticampus calculator lists 5 as follows:
1.6 Finalite MR-6
1.6 MR-6
1.6 MR-8
1.67 MR-7
1.67 MR-10
Also what is 1.7 EYRY
Any help is appreciated.
Bookmarks