$24 Headband Magnifer: https://amzn.to/2VIe6Ky
If sold out, these work well too: https://amzn.to/2W9dE6S

Adam goes through the different types of magnifying devices modelmakers can use for precision work, from handheld loupes to stereo surgical glasses. But the best type of magnifiers for both ergonomics, field-of-view, and depth-of-focus are just a simple set of headband magnifiers that you can get for around $20! Adam demonstrates why he likes this style so much, but we'd love to know what works best for you! 

Shot by Adam Savage

Jeweler's Loupe: https://amzn.to/2W2UFLr
20X Loupe: https://amzn.to/2zCOpm3
Surgical viewing glasses: https://amzn.to/2SfT5Vl