Vic Firth American Custom Keyboard -- Hard Phenolic 1 ball The M7s have a 1 1/8" phenolic ball for aggressive playing on bells and xylophone with black birch shafts for rigidity and consistency Vic Firth M7 American Custom Hard Aggressive Bell &amp; Xylophone American Custom Keyboard Mallets American Custom Keyboard Mallets are designed to address a range of instruments and all dynamic levels The unwound models deliver maximum sound With birch shafts for rigidity and consistency, they are favored by players who prefer extra reach without the added flexibility or rattan All Custom mallets are 16 inches long and come in pairs