SE 742DF File Set Tapered Diamond Needle, 3 mm x 140 mm x 70 mm (10 PC.) The file portions are 2.5mm, 4mm, 6mm, 8mm wide with blunt-flat tips Works on all natural materials marble, wood, stone, bone, etc. 7" (180mm) overall length; 2" working length; 180 to 320 grit Soft PVC-dipped handles have excellent grip even when exposed to moisture and fluids Used in deburring, fixing chipped glass and tile, and many hobbies and professional applications