https://www.amazon.com/gp/product/B0736JWRMG/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
This is the cheap alternative to doubletakes. I've had mine on for a year and drop the bike often they've never had a problem being dropped while folded. My buddy left his open and of course it broke the first drop, but that's why you're looking for folding mirrors. I leave them just loose enough to be able to fold without adjusting any screws and have never had a problem with hem shifting while riding or anything. I've seen people replace the allen key with a wing nut so you can adjust by hand, and use some gasket sealer on the ball joint because they said they rotated at speed but I've never had any issues at all.