The marimba is a percussion instrument consisting of a set of wooden bars struck with mallets to produce musical tones. Resonators attached to the bars amplify their sound. The bars are arranged as those of a piano, with the accidentals raised vertically and overlapping the natural bars (similar to a piano) to aid the performer both visually and physically. This instrument is a type of idiophone, but with a more resonant and lower-pitched tessitura than the xylophone.