Amazfit Helio Strap
Up to 10 days of battery at 20 g, and Amazfit says no monthly subscription is required. There is no screen and no GPS.
What the maker states
| Smartwatch battery | 10 days, Typical use |
|---|---|
| Weight | 20 g |
| Water rating | 5 ATM |
| Heart rate sensor | BioTracker 6.0 PPG |
| External sensors | Bluetooth (BLE): broadcasts HR to watches and treadmills |
| Training metrics | BioCharge, PeakBeats, 25 strength movements, 57 sports modes |
| App | Zepp App |
| Subscription | None for core features |
| Stored sessions | Offline heart rate storage up to 21 days |