I got it for my mother who fell. It connects to WiFi via an app. As soon as you press it, it rings on the phone wherever you are. It works just fine! I would like, if possible, to change the sound because the alarm siren is annoying. So far I haven't managed to do it. Maybe it requires a subscription.

Works and plays on tuya - smart life.
It is wifi, does not need a sim.
Almost plug and play and the battery lasts 4 weeks.
A minus is that it is a bit cumbersome and some services like phone notifications and sms notifications require a subscription if you really want them. (I chose not to pay for them)
Notifications through the app and through the mobile network are sufficient and are free.
They come even if smartlife-tuya is not running in the foreground.
If you leave smartlife open (in case you need to be on high alert), it also rings an alarm tone continuously from the phone's speaker.
Also, one last disadvantage is that I was told there is a similar one in a watch form and maybe the patient would be more willing to wear it permanently.
I hope no one ever needs it, guys...

Easy to use but you have to press several times for the notification to work. The notification sound is rather low

Even if it turns out to be unnecessary, I can receive a notification from a distance that my person is not well, even if the phone is out of reach to talk to me...