Guyker Two Way Dual Copper Head Acting Truss Rod - High Grade Steel Adjusting Rod Head Trussrod Acting for Electric Guitars Bass 440mm Luthier Tool

Part of guitar setup is truss rod adjustment to make the neck straight. 

Features:
Two Way Dual Copper Head guitar truss rod.
Total length is 440mm rod for making or repairs.
Made of high quality of steel.
Fast and easy to operate.
For all instrument types.
A must-have tool for pro luthier shops and home shops alike.

Note:
Please allow 1-2mm error duo to manual measurement.