File to crown Jumbo size fretsfrom 2.54mm to 2.8mm (0.100" and 0.110"). Once the frets have been set and radiused and the sides have been beveled, we will proceed to level and crown them. To do this, we can use this file. The handle is covered in plastic and allows a firm grip. The abrasive surface is curved to shape the fret at the ends. It comes with a practical plastic case for hanging on a tool panel.