https://youtu.be/ABv5LUt_AeY

In conjunction with USA Baseball and its other participating national member organizations, PONY Baseball adopted the USA Baseball bat standard (USABat) on January 1, 2018. Except for -3 (BBCOR certified), all other 2 1/4" and 2 5/8" barrel bats with a minus factor of (-5, -7, -9, etc.), must be USABat certified with the USABat licensing stamp on the bat in order to be used for league and tournament play.

Tee ball bats are not required to undergo lab testing to receive approval under the USABat program. However, to be approved for play, tee ball bats must carry the USA Baseball mark accompanied by the following text: "Only For Use With Approved Tee Ball Bats." .