This is a 12 inch 4R replacement blade for combination squares or can be used alone as a thick, rigid rule. This blade will make an excellent upgrade or replacement for both vintage or contemporary combination squares. Note: This blade will not interface with all brands of precision combination squares, but has been shown to fit most Starett, Mitutoyo, PEC and Brown & Sharpe 12, 18 and 24 inch combination square heads. This combination square blade is made from Japanese rust-resistant stainless steel that has been tempered creating a very stiff measuring tool that is quite resistant to flexing. The edges and ends have been ground parallel, straight, smooth and square. The blade is 1 inch wide by .080 inches thick. There is a groove running down on one side that is .100 inch wide x .040 inches deep. The 4R graduation feature quick-reading 32nds and 64ths on one side and 8ths and 16ths on the reverse. Graduation marks are produced via a photoengraving process creating very consistent and accurate markings with uniform gaps and line widths. Once etched, graduations are black filled for easy readability. Graduations are etched and not printed will not wear off with prolonged use. Graduations conform to strict international EEC 1 Accuracy Standards, i.e. +/- 0.2 mm at 20 Degrees C for 1000 mm Finish is non-glare satin chrome. A satin chrome finish minimizes scratches and corrosion and increases readability by achieving a brighter, non-glare finish that enhances the contrast between the black graduation lines and the surface of the rule. In addition, a satin chrome finish will not reflect light or glare. This is a replacement blade for combination squares or can be used alone as a thick, rigid rule. This blade will make an excellent upgrade or replacement for both vintage or contemporary combination squares. Note: This blade will not interface with all brands of precision combination squares, but has been shown to fit most Starett, Mitutoyo, PEC and Brown & Sharpe 12, 18 and 24 inch combination square heads. This combination square blade is made from Japanese rust-resistant stainless steel that has been tempered creating a very stiff measuring tool that is quite resistant to flexing. The edges and ends have been ground parallel, straight, smooth and square. The blade is 1 inch wide by .080 inches thick. There is a groove running down on one side that is .100 inch wide x .040 inches deep. Graduation marks are produced via a photoengraving process creating very consistent and accurate markings with uniform gaps and line widths. Once etched, graduations are black filled for easy readability. Graduations are etched and not printed will not wear off with prolonged use. Graduations conform to strict international EEC 1 Accuracy Standards, i.e. +/- 0.2 mm at 20 Degrees C for 1000 mm Rule. The 4R graduation marks feature quick-reading 32nds and 64ths on one side and 8ths and 16ths on the reverse. Finish is non-glare satin chrome. A satin chrome finish minimizes scratches and corrosion and increases readability by achieving a brighter, non-glare finish that enhances the contrast between the black graduation lines and the surface of the rule. In addition, a satin chrome finish will not reflect light or glare. Each rule comes in vinyl storage pouch. These are well made rules that will provide years of reliable service in any shop.