maximum diameter. -- the stringking metal pro usabat features the maximum allowable barrel diameter at 2 ⅝", giving you the best chance to make clean, powerful contact on every swing.maximum consistency. -- premium materials and precise manufacturing give metal pro usabat a big, powerful sweet spot that will hold up over the life of your bat and deliver consistent performance.balanced performance. -- the weight distribution of our metal pro usabat delivers versatile performance with the powerful swing of an end-loaded bat and the fast hands of a more balanced bat.premium materials. -- the high quality aluminum alloy used in the metal pro baseball bat is tougher than the metals commonly used in the aerospace, automotive, and military industries.