Precision ground diamond Pen files and Needle Files. The pen files are suitable for sharpening fishing hooks, darts, hunting knives etc. whilst the set of 4 needle are the ideal tool for sharpening carving tools etc and are also used in the British Aerospace industry. This range is a truly versatile set of pocket files that are electroplated with Monocrystalline Diamonds to enhamce performance. The pen style files simply unscrew from their case and screw back onto the case to make a steel type file for sharpening Knives, fishing hooks, dart points 600 Grit. Guaranteed for 5 years when used with TITMAN EDGE lapping fluid.