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

Middleton Baseball 10U and 12U:
-USA  or USSSA Baseball Marking are allowed
-2 5/8" Barrel Maximum
-NO BBCOR

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

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Middleton Softball 

-Marked as "Official Softball Bat" or "Official Fastpitch Bat"

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