This Polar Pro Soft Chest Strap is compatible with all Polar heart rate monitors and is designed for maximum comfort during intense workouts. It features a soft textile material, slip-preventing silicone dots, and a secure buckle. The integrated electrodes are engineered to minimize interference, ensuring precise heart rate monitoring. This chest strap is available in three sizes: XS-S, M-XXL, and XXXL. Please note that no sensor or heart rate monitor is included with this item. It is compatible with all H1, H2, H3, H6, H7, and H10 sensors. The strap also offers compatibility with Go Pro Hero 4 and 5, allowing you to view your heart rate on your Go Pro recordings.