Companies use several different methods for hardness testing, the most common being Brinell, Rockwell, Vickers, Leeb. However, there are disadvantages to each method: for Rockwell and Brinell, testing may lead to damage on the surface of a sample; for Vickers, only professional technicians are able to carry out tests smoothly; and for Leebs, the testing method is indirect, which may lead to a large deviation when converted to other scales.