NIKE AERO M1 BBCOR (MENS) Built for explosive contact with a stiff and highly powerful one-piece long-barrel Zr91 aluminum alloy. One-piece Zr91 alloy bat with Aero end-cap maximizes swing speed for serious impact power. Direct Connection for the player who wants the feel of metal and nothing else. Total stiffness comes from the one-piece design, for a direct power transfer on every cut. 2 5/8" barrel. BBCOR certified.