Mizuno Jennie Finch (-11.5) Fastpitch Bat The Mizuno Jennie Finch Fastpitch (-11.5) bat is made from Mizuno's new MZ-2200 aluminum alloy. Reduced swing weight helps to increase bat speed. Mizuno's new MZ-2200 aluminum alloy Lightweight -11.5 length to weight ration Reduced swing weight to help increase bat speed 2.25" barrell diameter