A cymbal stack is a combination of two or more cymbals mounted in contact, producing a sound unlike any single cymbal. The effect is similar to a loosely closed hi-hat, or can alternatively be seen as an extreme case of a sizzle cymbal with the upper cymbal serving as a single large jangle. The exact effect is dependent on the tension on the mounting bolt, and with some combinations can be varied from a very short crunch to a much longer buzz.