a flat wooden device approximately two inches high with a grip on top and sponge rubber on the bottom, with which the player strikes the keys. Its length spans an octave on a grand piano. The sponge rubber bottom is sculpted so that its ends are slightly lower than its center, making the outer tones of the octave sound with greater force than the intermediary pitches. The pianist can thus rush headlong through fearfully rapid passages, precisely spanning an octave at each blow.