Saw those advertised on social media and immediately questioned if they were any good !O/T but similarly O/T - anybody using any of the various business card size type trackers for iOS?
My personal theory - if any of them are good, they will be acquired by Apple. Or Apple will come up with their own version that works just as well (or even better).
Either way, I'm happy to wait until this particular technology proves itself before spending my hard earned cash.