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When repairing the LCD on my sisters ipod touch 6th generation I lost 3 1.6mm screws and some other screws for the lcd shield plate. Where can I purchase these tiny screws and other types of screws for other apple devices? I tried on eBay it says something like m1.6 and m1, m2, and m3 and so on. I have never heard of that type of screws before. What does this mean? Thanks

I have some years on Electronic Device Repair, and i never remember the screws size : ( https://www.ebay.com/itm/Apple-iPod-Touc