Used by many ATP Tournaments worldwide, the Tecnifibre X-One balls are considered to be the best balls in Tennis by many experts & Tournament Directors. They are manufactured using X D-Core technology which reduces the deformation of the ball by 20% even after prolonged period of play. The Tecnifibre X-One is made with 72% natural felt that makes the ball last longer than any other balls on the market. The balls come in 4-ball metal can. . There are 3 cans.