The rules for which bats can be used for each level is as follows. Some leagues and tournaments may have rules specific to them, but these are the official bat rules per Babe Ruth/Cal Ripken:

T-Ball:
USA Baseball T-Ball Stamp

Cal-Ripken Baseball (10U and 12U):
-USA Baseball Marking
-2 5/8" Barrel Maximum
-NO BBCOR BATS

Babe Ruth Baseball 13-15:
-USA Baseball Marking or BBCOR .50
-2 5/8” Barrel

Babe Ruth Baseball 16-18:
All Bats Must Be BBCOR .50

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Complete bat guide as of 2022: https://usabat.com/2022-usabat-guide/