Nanae Mimura Series mallets are slightly heavier than NZ Series mallets, and they feature latex-wrapped rubber disk cores covered by North American wool. The yarn is all natural wool (not chemically processed) and therefore particularly soft and durable. (Our yarn is purchased from the sheep farm that harvests the wool. The yarn is so natural that you may occasionally have to pick out a small piece of hay from a mallet head!) The softness of their yarn combined with the hardness of their latex-wrapped disk cores make NM Series mallets two-toned and very versatile.