Cell-free training balls. Quality training balls without celluloid.

Since the introduction of poly balls a few years ago, a number of manufacturers are marketing training balls. These are balls that are identical to their ITTF-approved 3-star cousins, with the possible exception that they are slightly less round, on average. Same weight, same hardness, same bounce.

Previously these balls were called 2-star or practice balls. They are commonly used when players want to use lots of balls to practice, so their practice is more concentrated on actual play rather than picking up the ball every time a rally ends. They also are used for multi-ball drills where the coach serves balls in a rapid-fire manner to the player who is practicing strokes, footwork, and/or other skills. Lastly, robot owners use these balls in their robots.

The manufacturer doesn't have to pay ITTF approval fees on these balls as they won't be used in sanctioned tournament play. So this lowers the manufacturing costs. 3-star poly balls run between $2–$3 a ball, making it very pricey to use 3-star balls when training with lots of balls. These training balls are the best alternative as performance is almost identical to tournament balls, but the price is often only $1–$2 per ball.

It's harder and more durable than most training balls. Most attackers like a harder ball, and most players these days are attackers, so this is a popular training ball.