DUPLEX Keyboard Percussion Mallets are available wound in cord or yarn and on a Delrin or Birch handle. The yarn mallets are hand wound and sewn with 4-ply 100% virgin wool over a unique grooved core. The heads are 1 3/8” in diameter. The cord mallets are tightly wound with 4- strand 100% cotton core. The head diameter is 1 3/8”.