I'm not sure I'd call it "must see," but for the people who like youtube it gets the job done. He covers the same material we've posted hundreds in times in threads. Picture quality is low resolution which makes it hard to see, and he doesn't go into enough detail. Would have been better if he described a couple more coins (he shows one DDO, and one MDD).
Here's a better one :https://www.bing.com/videos/search?...hine+doubling+vs+double+die+video&FORM=VQFRML
If you're looking for a must see on this topic, it's this article by JT Stanton: http://conecaonline.org/wp-content/uploads/2017/10/StrikeDoublingFlyer-1.pdf
Basically trying to say that on Cointalk most members prefer to see personally written posts and write ups.