Gauged DiamondCut™ Nut Slotting File Set for Electric Guitar - StewMac
Nut Files - Double Edge, for guitars, 3 sizes | Amplified Parts
Amazon.com: Guitar Bridge Saddle Nut Files Set - 13 Different Size Needle Files with Circular Cross Section and 9 Pcs Sand Paper For Bass, Ukulele, Acoustic & Electric Guitar nut slot polish -