The MusicNomad Truss Rod Neck Relief Measure and Adjust kit for Martin guitars simplifies the process of measuring and adjusting your Martin guitar’s neck relief, improving your playability and sound. The kit comes equipped with the 3 most common relief measurements for electric, acoustic, classical and bass guitars (.006”, .008” and .010”). When you are ready to adjust, the MusicNomad 5 mm premium truss rod wrench is made custom to fit all models of Martin guitar truss rod nut that you adjust inside the soundhole, except DSS-2018, OMSS-2019, Modern Deluxe Series and SC-13E. The ergonomic handle and rubber protective bumper gives you comfort and security while working around your prized instrument. The gauge can also be used on any other guitar or bass, and the 5 mm wrench is compatible with any other guitar brands that use that size.