What does 40+ ping pong ball mean?
What does 40+ ping pong ball mean? The reason the balls are labelled with 40+ is that when the ITTF made the plastic balls legal for competition, they also allowed the balls to have a bigger size tolerance. So a celluloid ball tends to be around 39.6mm whereas the new plastic balls measure around 40.2mm, making the plastic balls about 0.5mm bigger.