Detail 01
4mm size
Fits most makes of guitars.
Product detailSKU #1439818610535
DunlopGrooveTech Sound Hole Truss Rod Wrench 4mm
Independent shopping perspective
The Korena take
Built for acoustic-guitar truss rod work through the sound hole, the 4mm GrooveTech wrench tackles adjustment points a normal hex wrench may not reach. The blade is designed to clear the sound-hole opening and extend to recessed nuts, even when bracing sits in the path. A ball-end tip helps it locate in the nut, and the oversized screwdriver-style handle offers a secure grip while you make the adjustment. This 4mm size fits most makes of guitars.
Strong match
Who this is for
- Accessing a recessed 4mm truss rod nut through an acoustic guitar’s sound hole.
- Guitar maintenance on most makes that use a 4mm truss rod adjustment.
Consider the trade-offs
When to look elsewhere
- Guitars that require the 5mm truss rod wrench size.
What matters in use
The specifications, translated
Catalog numbers tell only part of the story. These are the details most likely to change how this product feels, sounds, or fits into a setup.
Detail 02
Ball-end tip
Helps guide the wrench into the truss rod nut.
Detail 03
Oversized screwdriver-style handle
Gives you a larger grip for the adjustment.
Final check
Know before you order
- 01Verify that the instrument’s truss rod takes a 4mm wrench.
Product questions
Before you decide
Straight answers to the questions shoppers most often ask about this product.
01Can it reach a recessed truss rod nut?
Yes. Its blade is designed to pass through the sound-hole opening and reach deeply recessed nuts.
02What guitars use the 4mm wrench?
The 4mm size fits most makes of guitars.
