The bottom line principle when it comes to making a baseball bat is the stronger the aluminum or composite material used to make it, the thinner the walls of the bat can be. Thinner walls allow for a better trampoline effect, making the ball jump off the bat harder. As new alloys are developed by the worlds largest metal provider ALCOA, the baseball bat industry is quick to pick up on the new technology, always looking for the alloy that is going to provide the thinnest walls with the greatest amount of durability.