Garmin Forerunner 630 - Black/White 2ND GENERATION RUNNING DYNAMICS -Calculates 6 advanced running dynamics: stride length, ground contact time balance, vertical ratio, cadence, vertical oscillation and ground contact time PHYSIOLOGICAL MEASUREMENTS -Supports advanced physiological measurements: stress score, performance condition, lactate threshold, recovery time, VO2 max, predicted race times BATTERY LIFE - Long-lasting, Rechargeable lithium-ion WIRELESS - Wirelessly transmits accurate heart rate to your compatible device SMART NOTIFICATIONS - See incoming email, text messages, call alerts, calendar reminders and more from your compatible smartphone.