This is an essential tool for adjusting truss rod nuts that are tucked away behind top braces.

This old style Larrivee truss rod wrench will fit Larrivee guitars with serial numbers 4001-39999. This wrench measures 3/16". This is 4.78mm or a little under 5mm.

Please note: Newer Larrivee guitars with serial numbers 40000-131999 require a smaller new-style wrench which measures 5/32" (3.97mm or a whisker under 4mm).