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So I've had one of these for around 7-8 months. At the beginning, it seemed to work well enough. Recently, my wife started to get notifications that she was being followed by an unknown tracker. It was, of course, the card in my wallet, despite the fact that I (and my phone) were right there along with it. It would repeatedly lose its connection with my phone, for whatever reason, resulting in a bunch of notifications for both me and whomever I was with.

Not sure if it's the battery (non-replaceable) in the Chipolo card going bad or what, but I've dumped it for an Apple AirTag and replaced my wallet with one that has a little AirTag pocket as many now do.
I use (and often curse at one set off when I sit down and push the embedded button in a) Tile. This has been very convenient but that embedded button can be annoying. I use AirTags AND Tiles and pbly won't add another product. However I WILL look at something that MIGHT replace the thin card-like Tile that has located my wallet thankfully a few times - lost at a restaurant, left at home and frantically grabbed after leaving/running back to home for a 3 hour drive once! .
 
i have no problem to securely put the AirTag inside my wallet. No card version needed.
Air tags are too large/fat to go in my wallet - which I keep slimmed down. Tile cards work ok but battery 1 year life makes Tile another throw away.
 
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