Garmin Forerunner 645 Music
Tech specs 
Size42.5 x 42.5 x 13.5 mm
MaterialPlastic with silicon band, stainless steel bezel
ChargingYes
Batterylithium-ion
Battery lifeSmartwatch Mode: Up to 7 days
GPS mode with music: Up to 5 hours
Water-resistance5 ATM
Weight42.2 grams
SensorAccelerometer, GPS/GLONASS, compass, optical HR monitor, barometric altimeter, gyroscope, thermometer
Displaysunlight-visible, transflective memory-in-pixel (MIP), colour 240 x 240 pixels, Corning® Gorilla® Glass 3
Screen size30.4 mm diameter
ColorsVarious
OtherPLATFORM: Proprietary OS
PROCESSOR: N/A
MEMORY: 200 hours of activity data; music storage for up to 800 songs
CONNECTIVITY: Bluetooth Smart, Ant+, Wi-Fi
Activity tracking 
StepsYes
DistanceYes
Calories burnedYes
ActivityYes
FloorsYes
SleepYes
Heart rate24/7
Vo2MaxYes
Stress & recoveryStress test
UV exposure
Skin temperature
Galvanic skin response
Hydration level
Calorie intake
GPSGPS and GLONASS enabled
Running featuresVO2 max estimate, recovery advisor, race predictor, running dynamics, calculates distance for indoor workouts, personal records, virtual partner/racer, cadence, performance condition, Training Status, Training Load, Training Effect and much more.
Swimming featuresPreloaded swim profiles, pool swim metrics (lengths, distance, pace, stroke count/rate, calories), stroke type detection (freestyle, backstroke, breaststroke, butterfly), swim efficiency (SWOLF), drill logging and more.
Other - automatic rep counting in the gym
- Features physiological measurements (stress score, performance condition and lactate threshold)
- Find my phone and more
Non-fitness functions 
Smartphone notificationsYes
On-board music storageYes, on-board storage for up to 800 songs
Connected payYes
Links 
Affiliate link*Amazon
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