Isomars Surgical/Pen Knife is widely used in industry as the top sharpening material. It is virtually everlasting, keeps its shape and sharpens the hardest materials eg. ceramic,stainless steel to the finest edge. The unique design of the file cross-section allows the sharpening of a multitude of different items . The sharpening rod can be retracted and stored within the anodised aluminium case. Simply twist the sleeve to lock/release the tool. Use the Flat Face of the tool to produce a razor sharp edge on any number of difficult to sharpen tools. Use the V shaped grooved channel for precision point sharpening e.g. darts, fishhooks, scribers, bradawls etc. Use the curved side to sharpen serrated blades or to smooth any other curved surfaces even glass chips. Use as small file for model making, metal or wood work. Includes one blade holder and three blades pack.