15 to 19-year-olds Players:
According to the Minnesota Youth Athletic Services (MYAS), 15 to 19-year-olds must have a bat that has a maximum diameter of 2⅝” at the thickest section. The bat must be 36" or less and have a weight differential of -3. An example of this would be how a 32" bat cannot weigh less than 29 ounces.
The NFHS also rules that:
The bat which may be a wood or non-wood product shall be a smooth implement, from the top of the cap to the top of the knob. All non-wood bats shall meet the Batted Ball Coefficient of Restitution (BBCOR) performance standard, and such bats shall be labeled with a silkscreen or other permanent certification mark. (Rule 1-3-2)
See the Minnesota High School Leagues (MNHSL), the National Federation of State High School Associations (NFHS), or the Minnesota Youth Athletic Services (MYAS)