Apple Watch Series 4Samsung Galaxy Watch Active
Tech specs 
Size40 mm (band fits 130-200mm wrists)
44 mm (band fits 140-210mm wrists)
40mm, 39.5 x 39.5 x 10.5mm (H x W x D)
MaterialSapphire crystal and ceramic back.Case Material: Aluminium
Strap: Fluoroelastomer
Case Crystal: Gorilla Glass
ChargingWireless chargingWireless Charging
BatteryLithium-ion230mAh
Battery life18+ hours45 hours (90 hours low usage)
Water-resistance5 ATM (50 metres)5 ATM
WeightCase weight: 30.1g (for 40mm version); 36.7g (for 44mm version)25 grams
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 sensorAccelerometer, Barometer, Gyro Sensor, HR Sensor, Light Sensor, GPS (Glonass,Beidou,Galileo), NFC
DisplayLTPO OLED Retina display with Force Touch (1000 nits), Ion-X strengthened glassSuper AMOLED, 360 x 360 pixel resolution
Screen size44mm: 977 sq mm display area (368 x 448 pixel resolution)
40mm: 759 sq mm display area (324 x 394 pixel resolution)
1.1" (28.1mm)
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, Green, Rose Gold, Silver
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
Operating system: Tizen 4.0
Processor: Exynos 9110 Dual core 1.15GHz
Memory: 768MB RAM + 4GB Internal Memory
Connectivity: 3G/LTE, Bluetooth®4.2, 802.11 b/g/n 2.4GHz, NFC, A-GPS/Glonass
Activity tracking 
StepsYesYes
DistanceYesYes
Calories burnedYesYes
ActivityYesYes
FloorsYesYes
SleepYes
Heart rateYesYes
Stress & recoveryYes
Pulse Ox
Respiration rate
UV exposure
Skin temperature
Galvanic skin response
Hydration level
Calorie intakeYes (through the app)
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).
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.
Other - ECG monitor
- irregular heart rate detection
- low or high heart rate alerts
- fall detection
Monitors blood pressure through an optional research app.
Non-fitness functions 
Smartphone notificationsYesYes
On-board music storageYes (Stream Apple Music direct to watch)Yes
Connected payYesYes
LTEYes
Links 
Affiliate link*AmazonAmazon | Samsung
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