Rectangular Gage Block Sets * Steel sets are produced from a special material featuring high carbon and chrome content * Stress relieved and heat treated to 65 RC; Extremely wear-resistant * Mirror-polished surface finish provides exceptional wringing characteristics * Individual serial numbers on each block, regardless of grade * Manufactured a temperature-controlled environment to provide precise and reliable accuracy * All blocks meet or exceed federal specification GGG-G-15C for flatness, parallelism and size, and conform to MIL-STD-45662A *With certificate Carbide Sets *Provides maximum durability under the most demanding conditions. *Especially recommended when exposure to abrasives may occur. *Outlasts and outperforms regular steel blocks every time. For more details, please kindly visit our website. In addition, we also supply the following products: (1) Measuring Tools------Vernier Calipers, Electronic Digital Calipers, Micrometers, Dial Indicators, Squares, Protractors, Gages, etc (2) Machine Accessories------Tool Post and Holder, Collects, Chucks, Drill Chucks, Milling Arbors, Sleeves, Vises, Working Tables, etc (3) Cutting Tools------including Drills, End Mills, Milling Cutters, Slitting Saws, Saw Blades, Reamers, Taps & Dies, Tool Bits, Carbide Inserts, etc (4) Machinery------Metal Working Machinery, Woodworking Machinery, Shear Bending and Rolling Machine, etc