Smart Rope is an LED-embedded jump rope that displays your fitness data in mid-air, as you work out.Smart Rope syncs with our mobile app, Smart Gym, to track your jump count, calories burned, and workout times. Stay motivated with interval training sessions, unlocking rewards, and competing with your friends. Unlike activity trackers or other wearables, Smart Rope uses the mechanics of the workout itself to generate accurate, relevant data you'll actually use to get better. Winner of the Good Design GOLD Award.Available in 3 sizes, please see sizing chart belowAvailable in 3 colors - Chrome, Black, GoldThe most efficient cardio - a truly anytime, anywhere workout23 high-quality LEDs embedded in a flexible yet impact-resistant ropeRope is housed at an innovative 45 degree angle, gliding across 4 sets of ball bearings for natural, effortless motionMagnetic sensors in the handles register one complete revolution of the rope as one complete jump, for accurate trackingPairs via Bluetooth 4.0LE to Smart Gym, our mobile app available on iOS and Android (Apple Watch and Pebble apps coming soon)Charges with standard micro USB cable (not included), 2 hour charge lasts for 36 hours of active use (about a month's exercise)Includes a zippered nylon soft touch pouch for maximum portabilityPlease Note Re: Sizing: Everyone jumps with a different stance, but generally shorter ropes are faster. If you're experienced with the jump rope, consider sizing down. Size: Rope length, excluding handles (jumper height range)S:   8' (5' - 5'4")M:  8'6" (5'5" - 5'9")L:   9' (5'10" - 6'2")