Washtub bass
（重定向自Gutbucket）
The washtub bass, or gutbucket, is a stringed instrument used in American folk music that uses a metal washtub as a resonator. Although it is possible for a washtub bass to have four or more strings and tuning pegs, traditional washtub basses have a single string whose pitch is adjusted by pushing or pulling on a staff or stick to change the tension.