These tennis balls are perfect for practice on the off season or playing a simple match with friends. These tennis balls are designed for soft surfaces or regular rubber courts for that consistent feel and reduced shock. This pack comes with 12 cans with 3 tennis balls in each can plus one BONUS can of 3 tennis balls. This set also includes an exclusive InPrimeTime tennis ball magnet for the car, refrigerator, or any other metal surface. Extra Duty felt is ideal for Hard Courts.