Fitbit Sense 2 Graphite Aluminum Shadow Grey Strap Advanced Health & Fitness Smartwatch, 24mm - FB521BKGB-US
which ends 06/28/2026
Fitbit Sense 2 Graphite Aluminum Advanced Health & Fitness Smartwatch 24mm Shadow Grey Strap
Take a closer look at your health and wellness with the Fitbit Sense 2 smartwatch. The easy-to-love smartwatch focuses on more than just fitness with features that help you keep an eye on things like stress, sleep and other health metrics. It starts with the cEDA sensor in the Fitbit Sense 2 smartwatch, which senses when you're experiencing signs of stress—all so that you can know where you are physically and emotionally, then reflect and respond appropriately. You might be more stressed than you'd expect due to a lack of sleep, too; Sleep Profile analyzes your sleep data across the month via ten sleep metrics, helping you understand how to find more restful sleep. And with the ability to store up to six days of battery life and quick-charge capabilities, the Fitbit Sense 2 is easy (and comfortable) to wear to sleep.
Bring Fitness Forward
When you're ready to work out after a great night's rest, the Fitbit Sense 2 is here to help. It starts with your Daily Readiness Score, giving you extra insight into the type of workout your body is ready for with Premium Membership. Other workout boosts available on the Fitbit Sense 2 include over forty exercise modes—keep track of whether you're lifting weights, going on a long bike ride, hitting the yoga mat or doing something else—and you'll see your stats on your wrist. Find even more fitness insights with your Cardio Fitness Score. And, as always, you'll see classic data like tracked steps, distance and calories in the Fitbit app on your phone thanks to the Fitbit Sense 2.
Smart Extras On Your Wrist
Fitbit is known for changing the game when it comes to tracking health stats, but the Fitbit Sense 2 goes further with the latest smart features. The latest health tech can measure your blood oxygen, test for irregular heart rhythms, test your skin temperature and more. Finally, built-in voice assistants like Amazon Alexa, the ability to receive Bluetooth calls via your watch and access to Google Maps all make the Fitbit Sense 2 smartwatch an impressive pick for the price. Order yours online from Abt for quick delivery, or reach out to our team of specialists if you have any questions. Read up online with our Learn Center's guide to smartwatches.
Features
- Manage Stress
Understand stress, then minimize its effects. Better sleep. Improved mood. More energy. Managing stress with Sense 2 can help you get there. Identify patterns of stress with all-day body-response tracking and smart notifications to remind you to reflect on your emotions. Try new ways of managing stress with guided breathing, exercise, meditations and more. - Sleep Better
Better understand sleep through science. Sense 2 helps you get the ZZZs of your dreams. Sleep Profile* breaks down your sleep data each month and pinpoints how you can improve your sleep based on 10 key sleep metrics. Check your Sleep Score to learn about the quality of your previous night's sleep, and get a breakdown of time in light, deep & REM sleep with Premium. - Health Metrics
Tune in to Your Body. Sense 2 + Premium helps illuminate changes in your wellness. Check your Health Metrics dashboard to see heart rate variability, skin temperature variation, SpO2 and more. You can also use the 90 days of health trends to uncover changes to your well-being. - Heart Health
Everything starts with heart. Use the ECG app for on-demand atrial fibrillation assessment or turn on irregular heart rhythm notifications to assess your heart while you're still or sleeping. Heart-rate tracking surfaces insights from your sleep, stress, activity and more while high & low heart rate notifications keep a close eye on your heart rate. - Fitness
Work out Smarter. Do what you love, just get more out of it. Daily Readiness Score* shows what level of workout your body is ready for, including an Active Zone Minutes goal and Premium workout recommendation. Track 40+ exercise modes and use built-in GPS for real-time pace and distance—even in up to 50 meters of water. - Google Smarts
The apps you love are here. Reach your destinations easier with turn-by-turn directions from Google Maps and make speedy, secure purchases from your wrist with Google Wallet. Coming soon.
Even More to Love
- The big picture of your health.
Premium uses data about your body to uncover your unique health patterns. It doesnt stop there: youll also receive personalized insights that empower you to make better choices plus access to workout and mindfulness videos.2 - Style & Comfort
Sense 2 is sleek and slim with raised band attachments that make it more comfortable for all-day wear. The modern design complements styles ranging from funky to formal. - Smart Info on the Go
Get notifications from your phone, pay for retail items, use the built-in voice assistant and send quick replies right from your wrist. - Battery for 6+ days
Sense 2 tracks all your health & fitness stats for 6+ days without having to stop for a charge. Plus get a full day's charge in just 12 minutes.
Stress & Sleep
- All-Day Body-Response Tracking
A cEDA sensor helps identify when your body is experiencing signs of stress so you can reflect on your emotions, take action and go on with your day. Use of the cEDA sensor may affect battery life. - Stress Notifications
Get notified when stress events are detected so you can respond with physical activity, deep breathing & more. - EDA Scan App For Stress Management
Do EDA mindfulness sessions on your wrist to help you relax—and get instant feedback on your stress. - Reflections
Log your mood and get in tune with your emotional stress. - Stress Management Score
See how well your body's handling stress each day. Detailed score breakdown available with Premium. - Relax Breathing Sessions
Do simple guided breathing sessions by following prompts on your wrist. - Sleep Tracking & Sleep Stages
Automatically tracks how long you sleep each night and time spent in light, deep and REM sleep stages. - Sleep Profile
Get matched with a sleep animal and see a personalized analysis of your sleep every month. Requires Fitbit Premium membership. - Sleep Score
Learn about the quality of your previous night's sleep with a personalized Sleep Score. - Smart Wake Alarm
Vibrating alarm wakes you during the optimal sleep stage so you feel refreshed.
Health
- SpO2 (Blood Oxygen) Tracking
Tracking SpO2 tells you how well blood oxygen is distributed in your body, which can help you understand potential changes in your wellness.*
- Irregular Hearth Rythm Notifications
Check for signs of an irregular heart rhythm that may be atrial fibrillation (AFib), so you can share this information with your healthcare provider.2 - ECG App for Heart Ryhtm Assessment
Compatible ECG app lets you assess your heart rhythm for atrial fibrillation—a heart rhythm irregularity—and share results with your doctor.*
- Resting Heart Rate
An important indicator of your heart health & fitness. In general, active people have a lower RHR. - High & Low Heart Rate Notifications
If resting heart rate is above or below your usual range, you get notified in the Fitbit app. - Heart Rate Variability
Tracks HRV–your time between heartbeats. A downward trend over multiple nights could potentially be a result of overtraining, lack of sleep, stress and more.*
- Skin Temperature Sensor
A built-in sensor tracks changes in your skin temperature to help you understand potential changes in your wellness.2
Only available in the Fitbit app and only displays variation. - Breathing Rate
Small variations in your breathing rate could be a sign of changes in your well-being.2
- Wellness Report
Get a PDF of your key health & wellness stats from the last few months that you can share with a healthcare professional.
Available with Premium. - Blood Glucose Tracking (In App Only)
Log your glucose levels and see how activity, sleep, stress & nutrition impact your trends in the Fitbit app. Advanced analytics available with Premium.2
- Menstrual Health Tracking
Log periods, record symptoms, find patterns in your cycle & estimate your ovulation window.3
Fitness
- Heart Rate Tracking
The heart of it all—heart rate powers important data like calorie burn, sleep stages, resting heart rate & more. - Daily Readiness Score
Find out if your body's ready to work out or needs time to recover. Available with Premium. - Active Zone Minutes
Tracks your time in heart rate zones so you get credit when you work harder. Workouts in cardio or peak zones earn double minutes. - Built-In GPS
See pace & distance on your wrist—no phone needed. - Exercise Modes
Track your favorite exercises like runs, bike rides, weights, yoga & more and get live stats on your wrist. - Steps, Distance & Calories
Displays stats on wrist and in the Fitbit app. - Swimproof
Water resistant to 50m for the pool, shower & more. - Cardio Fitness Score
Estimate your fitness level using your VO2 Max (how well your body uses oxygen during exercise). - Automatic Exercise Tracking
Auto-detects when you're exercising and records your stats in the app. - Workouts on Your Phone
Sweat to high-energy workouts in the Fitbit app, from Fitbit trainers & popular partner brands. Most workouts require a Premium membership.
Smarts & More
- Call, Text and App Notifications
See calls, texts & smartphone app notifications on your wrist when your phone is nearby. - On-Wrist Bluetooth Calls
Answer calls on your wrist, send callers to voicemail and adjust volume (when your phone is nearby). Coming Soon. - Alexa Built-In
Use Alexa Built-in to get quick news and weather, set alarms, control your smart home devices and more.6
- Google Maps
Easily get where you're going with an interactive view and turn-by-turn directions on your wrist. Coming soon. - Google Wallet
Make purchases from your wrist with Google Wallet everywhere Google Pay is accepted. Coming soon. - Fitbit Pay
Make purchases from your wrist with Fitbit Pay™.
- Find My Phone
Find your phone without making someone call it for you. - Always-On Display Mode
Keeps your display on at all times (may require more frequent charging). - Do Not Disturb & Sleep Mode
Mutes calls & notifications and turns your screen off. - Compatible with iOS and Android Devices
Fitbit devices are compatible with iOS and Android phones. - Slim Design
Sense 2 is built to feel natural on your wrist and complement styles both casual and elegant. It's sleek and slim with all-new raised band attachments that make it more comfortable for all-day wear. - 6+ Day Battery
Long battery life means less charging, more living.
Battery life varies with use & other factors. - Fast Charging
Get a day's worth of battery in just 12 minutes.
Battery life varies with use & other factors. - Clock Faces & Accessories
Give your Fitbit a stylish new look with dozens of clock faces and accessory bands to choose from. - Color Touchscreen
A bright color display for sharp stats all day. - Fitbit Premium Membership
Your Fitbit includes a for advanced insights, hundreds of workouts & mindfulness sessions, Daily Readiness Score, Sleep Profile & more.1
General
Case
Strap/Bracelet
Smartwatches
Approximate Dimensions
Warranty Information
Approximate Weight
Articles
Similar Products (5 items)
Frequently Asked Questions
-
The battery lasts up to 6 days on a single charge, allowing continuous tracking of health and fitness statistics. Additionally, it supports fast charging, providing a full day's battery life in just 12 minutes.
-
Yes, it is water resistant up to 50 meters (5 bar), making it suitable for swimming, showering, and other water activities without damage.
-
It features a multi-path optical heart rate sensor, electrical sensors for skin conductance and ECG capabilities, SpO2 blood oxygen tracking, skin temperature sensor, breathing rate monitoring, and irregular heart rhythm notifications to help monitor overall health and stress levels.
-
Yes, it tracks steps, calories burned, distance, and includes over 40 goal-based exercise modes with built-in GPS for real-time pace and distance without needing a phone. It also automatically detects exercise to record stats.
-
It is compatible with Apple iOS 14 or higher and Android OS 10 or higher devices, supports Bluetooth 5.0 connectivity, and integrates with an app for detailed health and fitness data, notifications, and personalized insights.