BOSI Polished 30HRC 0-180&iexcl;&atilde;Degree Two-Arm 600mm Metric Steel Protractor One piece stainless steel processed protractor with two protractor arms with hardness of 30HRC at least. Metric/inch scale. product name: Steel Protractor(metric/inch) Angle: 0-180; Specification: 600mm protractor arm number:2; material:2CR13 stainless steel; hardness: 32 HRC; color: silver tone; weight:150g