The device is intended for surface swimming. Scuba diving with the device may damage the product and will void the warranty.
NOTE: The watch has wrist-based heart rate enabled for swim activities. The watch is also compatible with the HRM-Pro™ series, HRM-Swim™, and HRM-Tri™ accessories. If both wrist-based heart rate and chest heart rate data are available, your watch uses the chest heart rate data.