Manufactured from chrome alloy steel and heat treated by a special process to guarantee sharper teeth for outstanding cutting performance on all hard and soft metals, including platinum. Checkering hand files are used for putting serrations on knife edges and to obtain a checkered designs A x B (mm): 20.3 x 5.0; Lines Per Square Inch (LPSI) & Lines Per Square Centimeter (LPSC): Cut 0 - LPSI: 30, LPSC: 12