The Fitbit Charge 4 Fitness Tracker monitors your Active Zone Minutes, heart rate, and sleep. Complete with detailed workout intensity maps. GPS is built-in, so you can leave your phone behind.
• Monitors heart rate / VO2 Max / blood oxygen / stress
• Battery life: Up to 7 days
• Water resistant & swimproof
• Compatible with Android / iOS
The Charge 4 automatically detects what type of exercise you're doing.