Fitbit Charge 2
Tech specs 
SizeWidth: 21mm
Small: 14 cm - 17 cm in circumference
Large: 16.5 cm - 20.6 cm in circumference
XL: 20.6 cm - 23.6 cm in circumference
MaterialFitbit Charge 2's wristband is made of a flexible, durable elastomer material similar to that used in many sports watches. Fitbit Charge 2 also has a surgical-grade stainless steel buckle.
ChargingUSB. Charge time: One to two hours.
BatteryLithium-polymer
Battery lifeup to 5 days
Water-resistanceSweat, rain and splash proof.
Weight36 grams
SensorOptical heart rate tracker, 3-axis accelerometer, altimeter, vibration motor
DisplayOLED
Screen size3.8 cm
ColorsBlack, Plum, Blue, Teal, Lavender Rose Gold, Black/Gunmetal
Other
Activity tracking 
StepsYes
DistanceYes
CaloriesYes
ActivityYes
FloorsYes
SleepYes
Heart rate24/7
Vo2MaxYes
Stress & recovery
UV exposure
Skin temperature
Galvanic skin response
GPSConnected GPS
Running features
Swimming features
Smartphone notificationsYes
Other Guided breathing
Links 
Affiliate link*Amazon | Fitbit
Read moreReview
*Disclosure: We are a professional review site that receives a small commission from sales of certain items, but the price is the same for you. See our affiliate disclosure page for more details.
**Manufacturers may update tech specs of their devices over time. While we cannot guarantee that the information on Gadgets & Wearables tech specs pages is 100% correct, we promise to review this content regularly and do our best to bring you the most precise information. To be absolutely sure of tech specs of a particular device, we recommend checking the manufacturer’s website.