This is the HRM-Dual heart rate sensor that came with the Garmin cycle computer Edge 840. This product costs 8,800 yen if purchased separately. I only tried it on because I was using a smartwatch to measure my heart rate. In addition to ANT+ connectivity, this comfortable soft strap heart rate monitor transmits real-time heart rate data via BLUETOOTH wireless technology, allowing you to connect to third-party training apps like Zwift from your phone or tablet, GPS watches, cycle computers, and even compatible fitness equipment and Garmin GPS watches or cycle computers used in your favorite classes. You can get accurate real-time heart rate data to take your performance to the next level in your year-round training. Dual Transmission In addition to ANT+ connectivity, this excellent heart rate strap now transmits real-time data via BLUETOOTH wireless technology, allowing it to communicate with Garmin GPS watches, cycle computers, and third-party training apps like Zwift from your phone or tablet. Comfortable to Wear The soft strap is comfortable and adjustable, and the heart rate module can be removed for washing. Data Synchronization Provides reliable and accurate real-time heart rate data when training indoors, outdoors, or online, allowing you to continue or improve your fitness. Specifications ・Waterproof rating: 1 ATM ・Module size: 34.0 mm x 62.0 mm x 11.0 mm ・Strap length: Adjustable from 63.5 cm to 132.0 cm (25" to 52") ・Weight: 54.4 g ・Battery: Replaceable CR2032 (3 volts) ・Operating time: Up to 3.5 years ・Wireless frequency/protocol: 2.4 GHz ANT wireless communication protocol, BLUETOOTH wireless technology 5.0 compatibility ・ANT+ connectivity and BLUETOOTH wireless technology