1. 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 it'll work on most stringed instruments.2. flat file, works on fret edge and fret end round.You will experience the amazing efficiency of diamond. The hand shank is made of solid wood: excellent grip and smooth operation.3. abrasive way to coarse for this application, use fret erasers makes the frets as smooth as buttery.4. It is made of high quality carbon steel& firmly coated with diamond-like grits. That ensure the long life service of this file.5.High Wear-resistant and excellent durabilitySize:227 x 20 x 20mmNet Weight:163g/0.36lbMaterial: steel + diamond matte + woodcolour: color+silverPackage Contents:1 x Fret File2 x Neck Protection Sheet the above package content, products are not included.Note: shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.