Material: rubber +PVC Diameter: 15cm Length of lanyard: 80cm Blue,Green 140g It is convenient to inflate, and the ball is tightly sealed without air leakage. It is convenient and quick to adjust the freely retractable shoulder strap of the lanyard. Seamless edges are connected seamlessly to ensure no air leakage. Distribution pump, convenient for daily use. Fix the arm swing posture and keep the correct swing trajectory. Synchronize your body and arms and establish a good swing habit.