The Vic Firth Articulate Series Keyboard Mallets are a comprehensive collection of sounds across Xylophone and Bells/Glockenspiel. With over 40 options spanning various materials, sizes, and weights, the Vic Firth Articulate Series is your one-stop-shop for finding the perfect sound, no matter the venue or repertoire. The M421 features a small 1" round poly core that works great on both xylophone and bells/glockenspiel.