The Heriba Double Bass String Winder is a fantastic little tool for changing strings, saving time and eliminating hand fatigue. Instead of laboriously turning the tuning mechanisms when restringing your Double Bass, the convenient and compact Heriba Double Bass String Winder is the perfect solution. This durable hard plastic part easily slips over the tuning machine-peg. The other end is comfortably gripped and turned until the old string can is removed and the new string can be installed. Fast and easy!