Fully Automatic and Intelligent Overnight Recovery Measurement applications give you daily feedback on how well you recover from stress and training during the night. This helps you make optimal choices the next day. The Training Load Pro and Recovery tracking tools help you optimize your training and avoid overtraining. Test your performance and personalize your heart rate, speed and power zones with the running and cycling performance tests. Our World-Renowned Optical HR Technology with 10 LED’s for deeper light penetration, and 4 detectors to sense light returning through the blood vessels to track your HR with precision. Ultra-Long Battery Life - up to 40h of training with full GPS and HR tracking (and even up to 100h with power save options). Up to 7 days in watch mode with 24/7 HR tracking. Premium Sleek Design for superior look and feel provides you with a high-performing, lightweight (only 52g) sports watch that won’t weigh you down whilst you train.