Hi! I would like to buy a Smartwatch, unfortunately 50€ is my top budget, but I would prefer to spend less. I’m using a Huawei p9 plus and I’m looking for a Smartwatch hoping that this would allow me to keep using this app without having the phone on the bed/onto the bed table. I’m buying this product only for this app, so I’m not interested in any spicy feature.
I would prefer a long lasting Smartwatch that doesn’t drain my cell phone battery. Hope you might help!
Good dreams 
Hello Giuseppe,
all the compatible wearables are listed here:
If the battery is your main concern, you might want to look for a band - those are incredibly long-lasting. All smartwatches usually require charging at least one in a couple of days, most of them need charging every day - especially if you’d use the watch also during the day to track the fitness activity. The battery, low price, and simple use are the main advantages for bands. The greatest disadvantage is the lack of API for most, so the integration is not direct and you need to install a companion app.
Smartwatch with the operating system won’t last that long, but offers additional features - this is highly individual if you would make use of those extra features. A few wearables even offer SpO2 tracking.
The quality of the accelerometer sensors is comparable among all the devices, so you don’t need to worry about the data quality.
If you are new to the smart wearable world, I think the bands might be the safest option, as they are available for a very reasonable price.
To make it sound less general 
I use MiBand 2 and I can’t complain - sometimes the BT connection is a little weaker, but I got it for about 8€, so I must admit it surprised me a lot (in a good way).
Thanks a lot! I bought a mi band 4 in the end and it’s working great! The app finally is tracking me perfectly even if I don’t sleep alone and we share a single mattress! Thanks again for the suggestion and Good night 