Excellent Condition Generation 2 Ring in Original Box: Infrared (IR) LEDs for monitoring nighttime heart rate and respiratory rate Accelerometers to capture daily movement, steps, and automatically detected workouts Negative temperature coefficient (NTC) sensors USB charger with white LED Titanium with physical vapor deposition (PVD) coating for Gold and Silver colors Titanium with diamond like carbon coating (DLC) for Black Nighttime resting heart rate, heart rate variability, skin temperature, and respiratory rate measurements Steps and daily movement tracking Automatic activity detection, without location services Body clock and chronotype, Explore content, and personalized activity goals are available for Gen2 rings.