Garmin Index Sleep Monitor S/M is the lightweight and breathable smart band to wear on the upper arm, designed to monitor sleep with maximum comfort. Provides sleep score, sleep stages, HRV status, breathing variations, skin temperature and much more, easily synchronizing data with the Garmin ConnectTM app for a complete physical fitness and recovery picture. Sleep score and Insights Saturation of oxygen in the blood (Pulse Ox) Classification of waterproofness: Swimming, 5 ATM Strap material: 70% nylon, 30% spandex, soft and elasticized Case material: Plastic Module Size: 41,7 x 37,6 x 7,8 mm S-M Size: 326 x 63,5 x 0.55 mm Module Weight: 14,5 g S-M Band Weight: 15,8 g Battery Type: Lithium Ions Battery life: up to 7 nights with SpO2 (typical use 8 hours of sleep) Charging: Owner charger Garmin Heart rate at constant pulse, every second, with rest rate Body BatteryTM monitor for energy levels Stress detection and night breathing variations Woman health functions: past ovulation and cycle monitoring Ox pulse sensor for blood monitoring