Rule 1.10
The bat must be a baseball bat which meets the USA Baseball Bat standard (USABat) as adopted by Little League. It shall be a smooth, rounded stick, and made of wood or of material and color tested and proved acceptable to the USA Baseball Bat standard (USABat).

Non-wood and laminated bats used in the Little League (Majors) and below, Intermediate (50-70) Division, and Junior League divisions, shall bear the USA Baseball logo signifying that the bat meets the USABat – USA Baseball’s Youth Bat Performance Standard. All BPF – 1.15 bats are prohibited. The bat diameter shall not exceed 2⅝ inches for these divisions of play. Bats meeting the Batted Ball Coefficient of Restitution (BBCOR) standard may also be used in the Intermediate (50-70) Division and Junior League Division. Additional information is available at LittleLeague.org/batinfo.
In all divisions, non-wood bat must have a grip of cork, tape, or composition material, and must extend a minimum of 10 inches from the small end. Slippery tape or similar material is prohibited.
NOTE 1: The traditional batting donut is not permissible.
NOTE 2: The use of pine tar or any other similar adhesive substance is prohibited at all levels of Little League Baseball. Use of these substances will result in the bat being declared illegal and removed from play.
NOTE 3: Non-wood bats may develop dents from time to time. Bats that have cracks or sharp edges, or that cannot pass through the approved Little League bat ring for the appropriate division must be removed from play. The 2-1/4-inch bat ring must be used for bats labeled 2-1/4. The 2-5/8-inch bat ring must be used for bats labeled for 2-5/8.
NOTE 4: An illegal bat must be removed. Any bat that has been altered shall be removed from play. PENALTY – See Rule – 6.06(d).