The Flexbar Hardness Testing File Set A unique set of six specially shaped files, each with a non-slip grip, color-coded handle. The Rockwell value is printed on each handle and the files range from HRc 40 through HRc 65. Flexbar precision testing files have specially curved tips which can reach into internal slots, grooves and bores which cannot otherwise be tested using conventional types of fixed or portable hardness testers. They can be taken out-of-factory sites to test for hardness on larg