Optimized Training for Endurance Athletes, For triathletes, runners, cyclists and endurance athletes who want to optimize their training, ZoneOptimizer adjusts your heart rate zones, making every session more effective, Sport profiles guarantee a quick and easy switch between different sports, Improves performance with endurance training programs, downloadable from polarpersonaltrainer, com with the Polar DataLink, Provides heart rate even in water with a comfortable and disturbancefree hybrid transmitter, Race Pace helps control your speed to reach your target time, Dimensions: 5, 04L x 2, 68W x 3, 78H, SKU: SPTMN4646