The GARMIN HRM-DUAL accurately measures heart rate. I was using it with a Garmin 965 to measure LT values. It accurately measures heart rate in real-time, making it ideal for monitoring and setting alerts during runs. If you want to accurately manage your heart rate, this is for you. It's overwhelmingly more real-time and accurate than wrist-based heart rate monitors. Wrist-based monitors, on the other hand, are slow to react and inaccurate. Furthermore, blood flow decreases in winter, sometimes making measurement impossible. If you're doing heart rate-based training, an electrode-based sensor is essential. Wrist-based measurement does have its advantages, and is ideal for 24-hour monitoring. I use the advantages of each. I am selling this because I purchased an HRM600. The retail price is 8800 yen (including tax), so I think it's a great deal. - Brand: GARMIN - Model: HRM-DUAL - Function: Heart Rate Monitor - Battery Type: CR2032 - Year of Manufacture: 2022 The strap can be used, but it is damaged, so please consider it as a bonus. I am also open to price negotiations. Please make an offer.