GD-JP-02-Pink Professional Aluminum Handle Jump Rope Fully Adjustable Speed Jump Rope with Steel Metal Bearings for Cross Fitness Training, Boxing, Crossfit, Master Double Unders 1.Lightweight aluminum handles allow for easy high speed maneuvers such as double-unders or crossfit. 2.The durable high-grade steel metal bearings are superior in every way to the cheap plastic ball bearings of other jump ropes. 3.Improves endurance speed and strength for boxing, crossfit, MMA and endurance fitness training. 4.The steel cable is coated with a PVC sleeve for protection and better durability.You can used the jump rope on smooth ground or plastic runway,but do not use in the rough concrete. 5.The steel cable is 10ft long, super lightweight and easily adjustable to the length needed for different users.