Fitbit FB521SRWT-US Sense 2 Advanced Health and Fitness Smartwatch - Lunar White/Platinum Aluminum

All-day Stress Detection

Recognize stressful events, manage them and move on with our new continuous EDA sensor on Sense 2. It helps detect stress events so you can start to see how and when your stress is triggered. Use of the cEDA sensor may affect battery life.

Stress Management Score

Get a handle on your stress. Higher score? You're showing fewer signs of stress. Lower score? Time to find better balance--try a meditation or go for a walk.

Sleep Profile

It's easier to get better sleep when you know what kind of sleeper you are. Find out whether your sleep mirrors a deep-sleep bear, a slow-to-sleep tortoise or one of our other Sleep Animals., then learn what habits best to support your profile.

Sleep Stages & Sleep Score

Learn about the quality of your previous night's sleep with a personalized Sleep Score. With Premium, see a breakdown of time in light, deep & REM sleep to see what's impacting your rest.

Fitbit ECG App & Irregular Heart Rhythm Notifications

There are two ways to uncover Afib, right at your fingertips. With the ECG app, you can take an assessment on demand. Plus, use irregular heart rhythm notifications to look for signs of Afib while you're still or sleeping.3

High & Low Heart Rate Notifications

Your heart rate is a key indicator of health, so Sense 2 keeps you informed when it's above or below your set resting threshold.

Daily Readiness Score

Enhance yoru workout routine with a Daily Readiness score that reveals if you're ready to push or should focus on recovery.

Active Zone Minutes

Get the results you want from every workout. Active Zone Minutes uses your heart rate to guide you toward your desired intensity level--then helps you get there.

Built-in GPS

See you real-time pace & distance without your phone using built-in GPS during outdoor activity, then see a map of your workout route in the Fitbit app.

40+ Exercise Modes

Sense 2 tracks more exercises than ever--like skiing, golf, stand-up paddle boarding and more--and see all your stats in real time.

Notifications

Get notifications for calls, texts, calendar events and apps like Gmail and Venmo--plus send quick replies and voice replies right from your wrist. Available when phone is nearby.

Calls From Your Wrist

Use the built-in mic and speaker to take Bluetooth calls hands-free, send callers to voicemail and adjust volume. Available when phone is nearby.

Google Maps

With Google Maps on your Fitbit watch, navigation is easier than ever. Explore a new route confidently with turn-by-turn directions on your wrist. (Phone must be nearby. Available on Android only, Coming Spring 2023 to iOS.)

Google Wallet

Tap your wrist to pay everywhere Google Pay is accepted. The quick, secure and contactless way to check out with your watch.

Built-in Voice Assistant

Use Amazon Alexa Built-in to get quick news and weather, set bedtime reminders and alarms, control your smart home devices and more--just by speaking to your watch.

6-month Fitbit Premium Membership

Get deeper insights and guidance, exclusive workouts, mindfulness sessions and more with the included 6-month Premium membership.

SPECIFICATIONS :

Touch Screen : Yes
Operating System Compatibility : Android, Apple iOS
App Compatible : Yes
Global Positioning : GPS, GLONASS
Metrics Measured : Activity vs. inactivity, Altitude changes, Blood oxygen, Breathing patterns, Cadence, Calories burned, Distance swam, Distance traveled, Duration of exercise, Electrocardiography, Heart rate, Hours slept, Laps swam, Pace, Route, Sleep quality, Speed, Steps taken, Temperature
Water Resistant : Yes
Maximum Depth of Water Resistance : 164 feet
Band Material : Silicone
Series : Sense 2
Case Shape : Rounded square
Band Type : Infinity
Clasp Type : Other
Display Screen : Yes
Touch Screen : Yes
Display Type : AMOLED
Color Display : Yes
Clock Display : Yes
Backlit Display : Yes
Adjustable Brightness : Yes
Customizable Watch Faces : Yes
Operating System Compatibility : Android, Apple iOS
App Compatible : Yes
Voice Assistant Built-in : Amazon Alexa
Data Plan Required : No
Bluetooth Enabled : Yes
NFC Technology : Yes
Wi-Fi Compatibility : None
Global Positioning : GPS, GLONASS
Mobile Notifications : Yes
Alert Type : Vibration, Visual
Silent Alarm : Yes
Vibration Alert : Yes
Built-In Microphone : Yes
Metrics Measured : Activity vs. inactivity, Altitude changes, Blood oxygen, Breathing patterns, Cadence, Calories burned, Distance swam, Distance traveled, Duration of exercise, Electrocardiography, Heart rate, Hours slept, Laps swam, Pace, Route, Sleep quality, Speed, Steps taken, Temperature
Multi-Sport Tracking : Yes
Sensors : Accelerometer, Altimeter, Ambient light sensor, Heart rate sensor, Pulse oximeter (Sp02) sensor, Temperature sensor
Number of Sensors : 7
Water Resistant : Yes
Maximum Depth of Water Resistance : 164 feet
Dust Resistant : Yes
Minimum Operating Temperature : -14 degrees fahrenheit
Maximum Operating Temperature : 113 degrees fahrenheit
Rechargeable :  : Yes
Charging Interface(s) : USB
Battery Type : Lithium-polymer
Replaceable Battery : No
Band Material : Silicone
Case Material : Aluminum
Size : Adjustable
Minimum Wrist Size : 5.5 inches
Maximum Wrist Size : 8.7 inches
Band Size : Adjustable
Product Width : 1.59 inches
Product Depth : 0.44 inches
Product Length : 9.79 inches