Has not yet been used; However, they appear to be of the highest quality. My complaint relates to square packing. All of the Model #01110 photos, including the GROZ corporate photos, show a molded plastic snap-in case with molded cavities for each square. Mine arrived in a small box with very thin foam dividers. The squares have only been inscribed with the GROZ name and logo, not the detailed descriptive information shown in all photos (this of course in no way affects the use or accuracy of the squares). Of course, the description of this product does not specifically state that a hard plastic case is included, EVERY SINGLE photo alongside the descriptive description shows the case. Slightly more enterprise precision and consistency is expected. One final note: these squares are made in India, but the information in the Revain ad only mentions that GROZ is an American company.