I have been using the heart rate sensor for about a year. The Velcro part of the belt has slightly lifted due to washing, but I don't think it's much of a problem in use. Please refrain from purchasing if you are concerned. Product weight: 19 grams Battery: Up to 30 hours Heart rate monitor: Optical heart rate sensor (6 LEDs) Main uses: Suitable for all sports (fitness gym, swimming, weight training, etc.) Main functions: Heart rate monitoring, heart rate zones, calorie consumption, training diary, etc. Size: M-XXL 23cm-32cm Body diameter: 30mm Thickness: 9.6mm Weight: 0.6 Operation: One button Bluetooth compatible / ANT+ compatible Regular price: ¥16,500 Running Trail running Triathlon Swimming Road bike