Features: This self practice tennis Balls with string is especially useful for improving tennis player strokes actions, and hitting precisions control. Make from natural rubber inner liner, tennis Balls is wearable, light weight and Enduring. The tennis Balls with string is small and light weight, easy to carry and store. Great teaching tool for beginners and intermediate tennis player to help to perfect skills of tennis, suitable for indoor and outdoor training and practice. You not need a tennis partners, and can have tennis training at any time and anywhere. Specifications: Materials: synthetic needle punched woolen fabric and natural rubber inner liner Diameter: about 6.5cm/2.56inch Note: Please allow 1-2cm errors due to manual measurement, make surely that you not mind before order. Due to difference between different monitors, the picture may not reflect the actual color. Package includes: 5Pcs Tennis Training Balls with String