The Metal Pro aluminum alloy baseball bat combines premium materials and superior manufacturing to deliver a powerful baseball bat with consistent performance. StringKing Men's Metal Pro BBCOR Certified Baseball Bat Premium Materials. The high quality metal alloy used in the Metal Pro baseball bat is tougher than the metals commonly used in the aerospace, automotive, and military industries. Consistent Power. Consistent BBCOR. We engineered the Metal Pro baseball bat to have a BBCOR rating that stays as high as possible throughout the barrel. It peaks at over .499 and stays consistent, giving you a wider sweet spot and more consistent power. Balanced Speed. Balanced Power. The Metal Pro baseball bat features a balanced weight distribution that's slightly end-loaded, giving you faster hands and a more powerful swing.