It is a carved hollow wooden instrument with a large slit. In its traditional form, the muyu, the shape is somewhat bulbous, but modern instruments are often rectangular in shape.^[3] They are generally played in sets of four or more to give a variety of pitches, in which they are also known as "tone blocks".^[4] In Western music, they can be traced back to early jazz drummers where they were sometimes called "dragons' mouths" before being later adopted into widespread orchestral use.^[5][6] An updated version of the instrument, known as "granite blocks", is made out of plastic rather than wood.^[7]

The sound of temple blocks is similar to that of wood blocks, although temple blocks have a darker, more "hollow" timbre.^[8] In their most common configuration of five, temple blocks are typically tuned to a pentatonic scale. Despite this, they are generally not considered pitched percussion.^[9]

Temple blocks are often used as sound effects, such as in Leroy Anderson's "The Syncopated Clock" and "Sleigh Ride", where they mimic a ticking clock and a galloping horse, respectively.^[10] They can also be used to reinforce the melody. John Barnes Chance's Incantation and Dance and Variations on a Korean Folk Song both have temple blocks introduce and double the motifs that appear within the music.^[11]