Babe Ruth Baseball ages 13-15 and 16-18 and Cal Ripken Division ball ages 4-12 have The decision is based on a study conducted by UMass-Lowell that determined some composite bats, after a break-in process, can exceed an acceptable bat performance factor (BPF) after a break-in process. What does this mean? It means that some bats test within the acceptable limits when new, but over time the bat exceeds the BPF. This of course translates to harder hit balls and a reduction in reaction time for defensive players.
Some composite bats do qualify so you need to know which ones to buy. I would recommend that you talk to your coach before you make the investment in a new bat.