. Diamond abrasive to coarse for this application, use rubber fret makes the frets smooth as buttery. The four-pointer socket is located in 1mm,2mm,3mm,4mm. 1mm works for extremely narrow frets, likes ukulele; 2mm works for all standard guitars, bass guitar, banjo, mandolin, guitar cigar box; 3mm, 4mm socket works on jumbo sills. This means that it will be suitable for most stringed instruments. It is made of the highest quality carbon steel and heavily coated with diamond groats. Which ensure the long life of this file. One flat file, works on the edge of the threshold and the round end of the threshold. You will experience the amazing performance of the diamond. The handle is made of high-quality solid wood: excellent grip and smooth running. Specification: Material: Carbon Steel + Diamond Grit + Wood HandleProduct Size: 227 x 20 x 2 0mm/8.9 x 0.79 x 0.79in Net Weight: 163g/0.36lbPackage Included: 1x Threshold is your file2 x Neck Protection. Note: Please allow 0-1cm error due to manual measurement. Make sure you don't mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you!