Ernie PO4118 Motorised String Winder:

The Ernie Ball Power Peg is the first of its kind self-contained motorized peg winder that allows you to restring your instrument up to 70% faster than traditional manual peg winders.

The Power Peg is powered by 4 AA batteries (not included) featuring a proprietary universal peg head that fits virtually all bass, acoustic, and electric guitar tuning machines.

Features:

• Handy and compact
• Fits into almost any gig bag
• Requires 4x AA batteries