DESC: ** FREE POLAR IR INTERFACE - FOR A LIMITED TIME AND FREE NEXT DAY SHIPPING! ** For runners who require the best. “If you can learn to run with a shorter faster stride in events like long distance triathlons, half or full marathons you will be more economical and consequently more likely to keep running for the entire event” says Olympic Triathlon Coach, Brendon Downey “Distance running performance is a function of fitness and running economy and there is no other running computer available that can help runners work on both these factors to anything like the level of the RS800." EKG-accurate heart rate displayed in either BPM, percent of max, or HRR Visual and audible target zone alarms Easy to read user configurable display with backlight OwnCal feature counts calories burned during workout OwnZone assists in automated setup of ideal target zones Sport Zones provide ability to quickly select and monitor training intensity Fitness Test with OwnIndex measures your aerobic/cardiovascular fitness in