Get fit. Sleep better. All in THE ONE™ WIRELESS ACTIVITY & SLEEP TRACKER If you want to turn fitness into a lifestyle, the One™ is for you. For starters, it never rests. During the day, it tracks your steps, distance, calories burned, and stairs climbed. Come nightfall, it measures your sleep cycle, helps you learn how to sleep better, and wakes you in the morning. The One™ motivates you to reach your goals by bringing greater fitness into your life – seamlessly, socially, 24 hours a day.