WHOOP Wearable Fitness Tracker

Features

As described by the manufacturer on Amazon.

• What You Get - A 12-month membership, WHOOP MG device, a SuperKnit Luxe band, and a waterproof* Wireless PowerPack. Choose from a range of band and accessory combinations, and add a waterproof Wireless PowerPack for on-the-go charging.
• HSA/FSA Eligible - All 12-month WHOOP memberships and battery packs qualify for HSA/FSA reimbursement.
• Screenless, Distraction-Free - No screen, no buzzing notifications. WHOOP focuses entirely on your health and performance, with up to 14+ day battery life so you can wear it around the clock.
• Heart Screener with On-Demand ECG - Take an ECG reading from your wrist in seconds to check for signs of atrial fibrillation. Heart Screener gives you a medical-grade view of your heart rhythm whenever you need it.
• 24/7 Health Insights - WHOOP monitors your heart rate every second of every day, delivering personalized Sleep, Strain, Recovery, VO2 max, Menstrual Cycle, and Heart Rate insights along with a Real-time Stress Monitor that pinpoints your stressors and shows how your body responds in the moment, so you can make better decisions about training, rest, and daily performance.