Garmin fēnix 6S

Overview:
Keep an eye on your heart with wrist-based heart rate and Pulse Ox.
Get more running and cycling stats than you know what to do with.
The world is yours to explore. Navigation sensors help you find your way back.
No matter where you go, text messages and alerts will always be able to find you.
No more fumbling for cash. Just use your watch to pay on the go.
Stretch battery life to the limit — go up to 9 days between charges in smartwatch mode.
Case Size:
42mm (the diameter of the watch housing)