Polar M400 vs. Garmin Forerunner 235 vs. Fitbit Flex vs. Garmin Vivosmart 4 vs. Amazfit T-Rex

 
M400
Forerunner 235
Flex
Vivosmart 4
T-Rex
 PolarM400Remove Buy NowGarminForerunner 235Remove Buy NowFitbitFlexRemove Buy NowGarminVivosmart 4Remove Buy NowAmazfitT-RexRemove Buy Now

Basic Info

Suggested Price$200$299.99$100$130$140
Release20142017201320182019

Activity & Fitness

Calories
Cycling (Bicycling)
Distance
Heartn/a
Oxygen
Sleep
Steps
Swim

Battery

Duration8 hours to 30 days9 days5 days7 days20 days
Rechargeable

Compatibility

Android
iOS
Windows Phonen/aNA
Mac
Windows

Connectivity

Bluetooth
Cellular
GPS
NFC
Wi-Fi

Display

Color
Resolutionn/a215 x 180NA48 x 128360 x 360
Sizen/a1.23 inchesNA0.74 inches1.3 inches
TouchNA
Typen/aMIPLEDOLEDAMOLED

Functions

Audio SpeakerAlerts only
Clock
Phone
Vibration
Voice

Hardware

Accelerometer
Barometer or Altimeter
Ultraviolet Sensor
Water Resistance3 ATM5 ATM1 ATM5 ATM5 ATM

Notifications

Phone
Emails
Texts

Software

Operating Systemn/aNABuild-in
Apps
Music

All Wearables