Active zone minutes alert you when you're in your personalized fat burn, cardio, or peak heart rate zones. After outdoor workouts, see a workout intensity map in the app that shows your heart rate changes along your route. Use built-in GPS to see your pace and distance on screen during outdoor runs, cycles, hikes, and more. Track sleep stages & review your in-app sleep score for an easy way to see how well you slept. Multi-day battery lasts up to 7 days and up to 5 hours when using built-in GPS. Varies with use & other factors. Use 24/7 heart rate to track resting heart rate & better measure calorie burn. 

Benefits:

• The latest health and fitness tracker from Fitbit comes with contactless payments as standard.
• The Fitbit charge 4 includes Fitbit pay, the company’s prepaid wallet that works with cards from nearly 500 issuers in 44 countries worldwide. Previously, charge buyers had to pay extra for a ‘special edition’ charge 3 to get built-in NFC payment functionality.
• Load your credit and debit cards to your wallet in the Fitbit app, then use charge 4 to tap and pay for purchases on the go — at transit stations, your favorite stores, and more,” says the company.
• The new device also offers GPS tracking, heart rate monitoring, Spotify compatibility, and the usual raft of fitness and exercise tracking features. Get call, text, and smartphone app notifications on your wrist. Plus, send quick replies to texts (android only). Available when your phone is nearby. Take your goals further with a health & fitness tracker that packs built-in GPS for pace and distance, 24/7 heart rate tracking, and more into a comfortable wristband.
• Use built-in GPS to see your pace and distance on screen during outdoor runs, rides, hikes, and more and see a workout intensity map in the app that shows your heart rate changes along your route with active zone minutes, feel a buzz when you reach your target heart rate zones during exercise, and celebrate when you earn extra minutes outside of exercise use 24x7 heart rate to track resting heart rate & better measure calorie burn.
• Syncing to mobile devices requires Bluetooth le and an internet connection. Syncs with mac os x 12. 2 and up, iPhone 5s and later, iPad 5 gen. And later, android 7. 0 and later see your spo2 nightly average and range on your wrist, and view trends over the past week in the Fitbit app (spo2 is not available in all markets.
• The spo2 feature is not intended to diagnose or treat any medical condition or for any other medical purpose) track your skin temperature each night to see how it varies from your personal baseline (not available in all markets.
• Only available in the Fitbit app and only displays variations. Not intended for medical purposes) track workouts in real-time with 20+ goal-based exercise modes.
• It’s also swim-proof and water resistant to 50 meters, so you can track swims, wear it in the shower and more multi-day battery lasts up to 7 days and up to 5 hours when using built-in GPS (varies with use & other factors). Track sleep stages & review your in-app sleep score for an easy way to see how well you slept

How to use it:
Open the Fitbit app and tap join Fitbit. Follow the on-screen instructions to create a Fitbit account and connect ("pair") your Fitbit device to your phone or tablet. The pairing makes sure your Fitbit device and phone or tablet can communicate with one another (sync their data).