Apple Watch Series 4Garmin Vivoactive 3
Tech specs 
Size40 mm (band fits 130-200mm wrists)
44 mm (band fits 140-210mm wrists)
43.4 x 43.4 x 11.7 mm
MaterialSapphire crystal and ceramic back.Case material: fiber-reinforced polymer and stainless steel
Lens material: Corning® Gorilla® Glass 3
Bezel material: stainless steel
ChargingWireless chargingUSB
BatteryLithium-ionRechargeable lithium-ion
Battery life18+ hoursGPS mode: Up to 13 hours
Smartwatch mode: Up to 7 days
Water-resistance5 ATM (50 metres)5 ATM
WeightCase weight: 30.1g (for 40mm version); 36.7g (for 44mm version)43 g
SensorAmbient light, optical heart rate sensor, Electrical heart sensor, improved accelerometer up to 32 g‑forces, improved gyroscope, GPS (GLONASS, Galileo, and QZSS), barometric altimeter, ambient light sensorGPS, barometric altimeter, compass, accelerometer, thermometer, heart rate
DisplayLTPO OLED Retina display with Force Touch (1000 nits), Ion-X strengthened glasssunlight-visible, transflective memory-in-pixel (MIP), 240 x 240 pixels
Screen size44mm: 977 sq mm display area (368 x 448 pixel resolution)
40mm: 759 sq mm display area (324 x 394 pixel resolution)
1.2" (30.4mm) diameter
ColorsA number of aluminum finishes anodized in silver, gold and space gray. You can also pick up the device in gold stainless steel with a matching Milanese band, joining the silver and space black stainless steel models.Black, White
OtherPLATFORM: watchOS
PROCESSOR: S4 with 64-bit dual-core processor, W3 Apple wireless chip
MEMORY: 512 RAM, 16GB storage
CONNECTIVITY: Bluetooth 4.0, NFC, WiFi, LTE and UMTS cellular radio
PLATFORM: Home Grown OS
PROCESSOR: Unknown
MEMORY: 7 timed activities, 14 days of activity tracking data
CONNECTIVITY: WiFi, Bluetooth
Activity tracking 
StepsYesYes
DistanceYesYes
Calories burnedYesYes
ActivityYesYes
FloorsYesYes
SleepYesYes
Heart rateYesYes
Stress & recoveryYes
Pulse Ox
Respiration rate
UV exposure
Skin temperature
Galvanic skin response
Hydration level
Calorie intake
GPSYes (GPS,GLONASS, Galileo, and QZSS)Yes
Running featuresWatch displays up to 5 metrics during your run (time, distance, current pace and average pace, heart rate, active calories or total calories).Preloaded running profiles, GPS based distance/time/pace, run workouts, foot pod capable
Swimming featuresPool swim and open water swim. At the end of a swim, the watch displays the time of day the activity took place, dominant stroke used (auto-detection is used), distance, workout time, pool length, laps completed, average pace, average heart rate, and both active and total calories burned, as well as the weather at your location. Preloaded swim profiles; Pool swim metrics (lengths, distance, pace, stroke count/rate, calories); Stroke type detection (freestyle, backstroke, breaststroke, butterfly); Pool swim workouts
Swim efficiency (SWOLF)
Other - ECG monitor
- irregular heart rate detection
- low or high heart rate alerts
- fall detection
- gym workout tracking
- music control, find my phone, etc..
- Built in apps for running, golfing, cycling, swimming, snowboarding/skiing, paddle board, rowing, cardio, walking, strength training, rep counting, yoga, eliptical, stair-stepper and more.
Non-fitness functions 
Smartphone notificationsYesYes
On-board music storageYes (Stream Apple Music direct to watch)
Connected payYesYes
LTEYes
Links 
Affiliate link*AmazonAmazon
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