Really convenient and it seems to work just fine as the values are close to those from my watch. It’s worth the money.
Only downside is the default vibration alarm set to 180 BPM. It quite annoying and to deactivate or set it to other value one has to download an app and register, which seems to be a lot of effort for such a small thing.
It was a very good device. Unfortunnully
Is now broken by a fall