I've used an Optivisor since around 1980 for engraving, checkering and just about every other sort of bench work. I have a #10 lens in it and have always used that one. It's only 3.5x,,wish it was more sometimes but the working distance is down to about 4 inches already. Puts my snout kinda close to the spinning lathe chuck as it is.

I've cracked the plastic frame of the visor a couple times (my fault), but it super-glues nicely back together. The forehead pad is about gone but still usable.
Can't work w/o it. After the lights go on in the shop, the next thing that happens is the Optivisor goes on my noggin.

Before I used that, I used a small jewelers loop that clamped on my eyeglasses. That worked out OK for a while especially doing detail work. .
Thinking back when I first started engraving, I didn't even need any loop or magnifier or anything. Something to be said for being young!

I'd stick with their product if I have to buy another.