best of the file guides for manual sharpening?

[R/C Pilot]

At 59 years old magnifiers help my chain sharpening a lot, as did a cheater lens help my welding. You have got to be able to see exactly what you are doing to be able to do a proper job of sharpening chain. I also have my vise jaws 51" above the floor. I use just a file, magnifiers and vise, and guage all cutter lenghts when sharpening in my shop.

 

[Tzed250]

Has anyone seen or used one of these FG4 guides, its similar to the Husky roller guide.

YouTube

That is great!!!