https://www.dickblick.com/items/handheld-magnifier-2-x-4-rectangular-bifcoal-2x6x/
Handheld Magnifier - 2" x 4", Rectangular Bifcoal, 2x/6x | BLICK Art Materials
Shop Handheld Magnifier - 2" x 4", Rectangular Bifcoal, 2x/6x at Blick. Find everything you need for your next creative project online.
2 x 4handheld magnifier
https://www.afb.org/aw/15/12/15614
A Review of Prodigi Duo, the Electronic Magnifier by HumanWare: When Desktop and Handheld...