Polar M400 vs. Casio WSD-F20A vs. Fitbit Flex vs. Apple Watch Series 4 vs. Fitbit Inspire HR
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| PolarM400Remove Buy Now | CasioWSD-F20ARemove Buy Now | FitbitFlexRemove Buy Now | AppleWatch Series 4Remove Buy Now | FitbitInspire HRRemove Buy Now |
Basic Info | |||||
| Suggested Price | $200 | $399 | $100 | $329 | $99 |
| Release | 2014 | 2018 | 2013 | 2018 | 2019 |
Activity & Fitness | |||||
| Calories | |||||
| Cycling (Bicycling) | |||||
| Distance | |||||
| Heart | n/a | ||||
| Oxygen | |||||
| Sleep | |||||
| Steps | |||||
| Swim | |||||
Battery | |||||
| Duration | 8 hours to 30 days | 1 day | 5 days | Not Yet | 5 days |
| Rechargeable | |||||
Compatibility | |||||
| Android | |||||
| iOS | |||||
| Windows Phone | n/a | NA | |||
| Mac | |||||
| Windows | |||||
Connectivity | |||||
| Bluetooth | |||||
| Cellular | |||||
| GPS | |||||
| NFC | |||||
| Wi-Fi | |||||
Display | |||||
| Color | |||||
| Resolution | n/a | 320 x 320 | NA | 384 x 480 | 139 x 60 |
| Size | n/a | 1.32 inches | NA | 1.78 inches | 1.4 inches |
| Touch | NA | ||||
| Type | n/a | LCD | LED | MicroLED | OLED |
Functions | |||||
| Audio Speaker | Alerts only | ||||
| Clock | |||||
| Phone | |||||
| Vibration | |||||
| Voice | |||||
Hardware | |||||
| Accelerometer | |||||
| Barometer or Altimeter | |||||
| Ultraviolet Sensor | |||||
| Water Resistance | 3 ATM | 5 ATM | 1 ATM | Not Yet | 5 ATM |
Notifications | |||||
| Phone | |||||
| Emails | |||||
| Texts | |||||
Software | |||||
| Operating System | n/a | Wear OS | NA | Watch OS 5 | Fitbit OS |
| Apps | |||||
| Music | |||||