The OS Dual Heart Rate Monitor provides real-time analysis of heart rate and performance metrics during aerobic activity. The comfortable strap lies smoothly against the skin and can communicate stats with a range of GPS devices and smartphone apps. The information it records can be used to refine, improve and push through your personal bests.Chest strap provides accurate heart rate dual communicationCompatible with GPS devices by OS or other brandsConnects to both Android and iOS smartphone appsAnt+ and Bluetooth smart connectivityRecommended activity - running / training / cycling