The Diamond-Coated Nut File from Music Nomad features a revolutionary round "string-shape" blade design for smooth, precise cuts. Able to cut and polish slots simultaneously, this 150 grit nut file won't drift like common toothed files. The industrial, even diamond coating cuts all nut or saddle materials such as nylon, bone, graphite and TUSQ. With an ergonomic handle provides total comfort and control, this nut file is great for electric, acoustic and classical guitars, as well as 5-string basses.