These metal hardness testers can measure hardness in any known metal hardness scale as also can covert readings of any scale to any scale. further more, in particularly harsh working environments or for more comfortable handling these metal hardness testers can be stored in a protective bag. To date, Yamayo Bliss metal hardness testers are unmatched in their implementation of the portable metal hardness tester concept and have therefore become established as a globally recognized measuring technique. These metal hardness testers meet the customers'' needs for a non destructive metal hardness tester.