Fine design: it can provide stable support for training, as the base has a valve for inserting sand or water to increase the weight, and the small ring on the side for hanging the band, the concave part for placing the tennis ball , convenient and convenient to use. Easy to use: easy to use and convenient for training without ball picking. It is lightweight and portable and helpful for practicing with one person. It could also improve your concentration, your sporting skills, hand and eye coordination and develop the interests of sport. PERFECT GIFT: A great gift for your friends, family members and kids who like to play tennis. It can help improve your stroke action, leg work and impact strength. Precision control, tennis skills, suitable for many places such as garden, park etc. Item package: 1 x trainer base, 1 x training ball Product description Material: plastic + rubber. Color: blue. Base size: approx. 15 x 20 x 5 cm / 5.9 x 7.87 x 1.96 inches. Ball seat size (diameter): approx. 6.3 cm. Elastic force of the ball: approx. 1.2 m. Elastic force of the bandage: 4 - 8 m / 13.12 - 26.24 ft. Approximate weight 270 g.