DeMarini Steel Slow Pitch Softball Bat 13 inch carburized steel barrel: featuring a proprietary and patented heat-treating process for increased performance and durability Znx alloy handle: by increasing stiffness and durability, the znx alloy handle flexes less and forces the barrel to deflect more for increased overall barrel performance 6mm grip and rock knob: new grip and more comfortable knob added for improved feel and design USSSA, NSA, ASA, and ISA approved