Feature:1. Basic Specifications: The size of the mounting hole of this guitar knob is about (L x W) 3.8mm4mm, which is easy to use2. Ebony+Metal: The guitar knob is made of high quality ebony+metal materials, which makes feel more comfortable to the touch, exquisite workmanship, good texture3. Scope of Application: This is a peg buckle handle that is widely applicable to the head button of electric guitars and folk classical guitars4. Long Service Life: The guitar knob is environmentally friendly, odorless, and durable, stable in performance, and long in service life5. Elegant Appearance: This is a peg buckle handle, with an elegant appearance, and is beautiful guitar head decorationSpecification:Item Type: Guitar Tuning Peg ButtonsMaterial: Ebony + MetalColour: Black.Package List:6 x Guitar Tuner Button6 x Screw6 x White Washer6 x Black WasherNote:Only approximate size for tuner button mounting hole for reference, can not be totally exact. Only the approximate for reference. Customers can be be sure if this mounting hole is too big to install according to this size. But if the mounting hole is too small for you, would be hard to fit in. If so, please enlarge the hole with small file. So that this problem can be saved. Please check all very carefuly before order. Thanks for your cooperation.