Feature: 1. 1. Four gauges slot are provided in 1mm,2mm,3mm,4mm. The 1mm slot works for extra narrow frets, likes ukuleles,The 2mm slot works for all standard guitars, bass, banjo, mandolin, cigar box guitars, The 3mm,4mm slot works for jumbo frets. That means it'll work on most stringed instruments. 2. 2. One flat file, works on fret edge and fret end round.You will experience the amazing efficiency of rhinestone. 3. 3. Compatible with not only suitable for crowning guitar fret, but for electric guitar, acoustic guitar ,bass, Ukulele etc, a nice simple way for crowning frets if they are worn. 4. 4. Diamond abrasive way to coarse for this application, use fret erasers makes the frets as smooth as buttery. 5. 5. It is made of high quality carbon steel& firmly coated with diamond-like grits. That ensure the long life service of this file. Specification: Material: Carbon steel, rhinestonegrits, wood handleProducts Size:195*10*10mm(7.7*0.4*0.4inch)Net Weight:140g/0.32l Package List: 1* Fret File2* Fret Protection Sheets