The Ernie Ball 4117EB Power Peg Pro is a motorized peg winder which allows you to restring guitars and basses much faster than if you did so using a manual peg winder.
Powered by a rechargeable lithium-ion battery and equipped with more torque than the Standard model, the Power Peg Pro features a proprietary peg head that fits the tuning pegs of all acoustic, electric, and electric bass guitars.
Specs:
It also works with the tuning pegs of mandolins and ukuleles