Mitutoyo Steel Rectangular Gage Block Set (81 blocks per set) BLOCKS INCLUDED IN SET... 9 Blocks: .1001" - .1009" in .0001" increments 49 Blocks: .101" - .149" in .001" increments 19 Blocks: .05" - .95" in .05" increments 4 Blocks: 1" - 4" in 1" increments Grade 0 Precision gage blocks are the primary standards vital to dimensional quality control in the manufacture of parts. Mitutoyo offers a complete selection of gage blocks available in a choice of rectangular or square, metric or inch. Accuracy Gage blocks offered by an all-round precision measuring machine manufacturer, Mitutoyo, guarantee such a high accuracy that users can use them without anxiety. Needless to say, Mitutoyo has established a traceability system for our measurement products, up to the Metrology Management Center of the National Institute of Advanced Industrial Science and Technology (AIST) and we have been certified by the Japanese government as an accredited laboratory. Wringing The lapping technique is one of Mitutoyo's specialties. Our advanced lapping technique, developed for more than a half century, enables us to achieve the best flatness and surface roughness needed for gage blocks and realize a great wringing force. Abrasion Resistance and Dimensional Stability High-carbon high-chrome steel is employed to sufficiently satisfy a variety of material characteristics required for gage blocks. A high degree of hardness, obtained by our heat treatment technology and that reassures users, as well as methodically repeated heat treatment, have successfully reduced deterioration change over time to the minimum.