Hardened steel plus HRC 55 Precision Ground throughout The Mitutoyo 010014 Angle Block - has the following specifications: Primary Angle: 30, 60, 90 Degree Accuracy: +/- 40 sec Type: Angle Block Material: Hardened Steel Features: Hardened steel over HRC 55 Precision ground throughout Material Steel Brand name Mitutoyo Number of items one Model number 10001 Part number 010001 Specific uses of the product Angle Block