💪 Elevate Your Heart Rate Game! Experience unparalleled accuracy in heart rate monitoring. Designed to keep up with your active lifestyle, rain or shine. Transform your phone into a powerful fitness tracker. Seamlessly connects with all your favorite devices. Enjoy workouts without the bulk—just 100g of pure performance. Waterproof ANT+ & Bluetooth Replaceable Battery The Polar H9 Heart Rate Sensor is a top-tier, affordable heart rate monitor designed for fitness enthusiasts. With advanced ANT+ and Bluetooth connectivity, it easily pairs with various devices, ensuring accurate heart rate tracking across all sports and activities. Its waterproof design and replaceable battery make it a reliable companion for any workout, while compatibility with popular fitness apps enhances your training experience.