hi-hat
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A hi-hat is a set of two small, matched cymbals, 30–35 centimeters (12–14 inches) in diameter, placed on a stand horizontally and operated by a foot pedal. The lower cymbal is stationary, faces upward, and is attached to the stand, while the upper cymbal is moveable, faces downward, and is attached to a spindle that runs through the body of the stand. As the pedal is depressed, the top portion of the high-hat comes together with the lower portion. The upper cymbal can be struck with a stick in a closed or open position, making a short or sustained sizzling sound as the two cymbals
A hi-hat clutch is an accessory that holds the top cymbal in place.
A drop clutch is a specially made hi-hat clutch that allows the top cymbal to drop when a lever on the side of it is hit. This accessory is used with double bass drumming.