Built with a slim design and an always-on, full-color display that’s light on the wrist and easy to read even in direct sunlight — 41 mm Smaller-sized Forerunner 255S Music provides up to 12 days of battery life in smartwatch mode and up to 26 hours in GPS mode for a full picture of your health — from sleep to training Download up to 500 songs to your watch, including playlists from Spotify, Amazon Music or Deezer and connect with your wireless headphones for phone-free listening Morning report summarizes your sleep, HRV status and daily workout suggestion in one place as soon as you wake up (This device is intended to give an estimate of your activity and metrics) Get training tips, personalized daily suggested workouts and completion time predictions based on course details, weather and performance View your entire week of daily suggested workouts, which adapt after every run to match your performance and recovery HRV status tracks your heart rate variability while you sleep, giving you greater insight into your overall wellness, recovery and training performance (This device is intended to give an estimate of your activity and metrics) Get free adaptive training plans from Garmin Coach for a 5K, 10K and half-marathon, or create your own custom workouts in the Garmin Connect smartphone app Evaluates your current training status to indicate if you’re undertraining or overdoing it; offers additional performance monitoring features, including recovery time after your workouts