The barrel-to-handle connection is held together using the TRU3 piece, which significantly eliminates vibration and efficiently transfers contact energy back to the barrel. Speaking of the barrel, Louisville uses a Grit Blast Finish to create more spin on the ball. This spin will increase the intensity of your hits, making them go further at a faster speed. Lastly, the Z4's have a 7/8" Tapered Handle, 12" Barrel Length & the standard slow-pitch 2 1/4 Barrel Diameter.Balanced - Made for contact hitters, this Z4000 has a Balanced weighting for increased swing speed and improved bat control. USSSA - This bat is approved for USSSA, NSA and ISA softball associations. Association Approval: USSSA, NSA and ISA (Not approved for ASA or ISF).