FLYZOE Speed Ropes with Calorie and Jump Counter For Exercise and Fitness Activities Adjustable length, one size fits all. Non-slip handle are designed to reduce hand fatigue during longer workouts. Digital jump rope can keeps track of calories burned and count numbers; and perfect for all experience levels, exercise, cardio, boxing, workout and fitness. Portable and compact, so you can throw it down in your gym bag, lunch bay and take it anywhere you go. Lightweight and suitable for adult, children student and pupil, no age limitation; enhance children's growth and improve their intelligence.