This is a tennis training device. Sold as one piece. It has a bearing, so it rotates well, allowing for enjoyable practice. By applying spin to the ball of the training device as shown in the second photo, you can naturally develop wrist work. It is also used in club activities and has been very well-received, with users achieving excellent results. The third photo shows the results of training with this training device. It is handmade, and there may be some rough spots, but the effect is outstanding. (Individual results may vary) Please understand the above before purchasing. Please note that it may take some time to ship. Please note that the racket is not included. The photos are reused, so they may differ slightly from the actual product. Used tennis balls will be provided.