Mayyven is a good example of a startup building for a massive market (the hair extension industry is $5B in the U.S.) that many people aren't familiar with because they're not the consumer.
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I, too, have always wondered about the answer to this question. Hair extensions are very strong and thick. Here https://lifeofhair.com/source-great-lengths-extensions/ you can read more about what kind of hair they use in Canada for hair extensions. Personally, I didn't even know about that. Very interesting.
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