That 80% on the lower left, it's the battery level of my Tesla :-) I modified the Crystal watch face to query my car for its charge and display it on my
Garmin HRM-DUAL Heart Rate Strap In-Depth Review | DC Rainmaker
How long do HRM-Tri batteries last? – Chris Worfolk's Blog
Battery Replacement Instructions for Premium Feature HRM Straps | Garmin Customer Support