Oh sorry, yes. Anti Newton ring glass. If you press a film surface hard and flat against glass you'll see weird rings appearing. 'newton rings'.
ANR glass is a kind of 'frosted' or 'roughed up' glass that prevents this kinds of rings.
But that also means the glass has a structure to it, and if you put that glass between your film and your scanning device, that structure will show up and remove sharpness and detail.
If you put it between the backlight and the film, it acts as a little diffuser and you get nicely lit film strips , and you can press it flat against the ANR glass so that no rings will show up.
ANR glass can be quite expensive although there are some 'price fighters out there'.
I have two strips exactly the same of a 6-strip row of 35mm film , I think it's meant to be used in the v700 holders or something. And I have some cheap empty slides that have ANR glass in them , which I break open when I want to try another DIY film holder. Like I said , so far nothing that I'm really happy with.
Maybe I'll buy a cheap reflecta / Pacific Imaging scanner around the 1800 DPI mark for cheap on eBay, and rip it open and use the plastic shell with it's film holder to place it on my lighttable