Nike SDM Tailwind:
An essential measurement tool for trail runners and anyone who likes to vary their training courses, Nike's SDM Tailwind records your speed, distance, average pace and calories burned wherever you decide to run or walk. The lightweight design locks over your laces and features an intuitive two-button interface that's extremely easy to master. Because the patented speed sensor technology registers speed and distance data with 97% accuracy, you'll find that calorie burn calculations are more reliable than some heart rate monitor watches with calorie burn functions. Unlike sport chronographs that require an exclusive jeweler's tool for changing the battery, the SDM Tailwind battery hatch is readily accessible so you can change batteries without paying for the service.
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