Accuracy: ?2″.
To inspect protractor, taper gage, index plate, index head and goniometer, can also be used to set angle.
Made of special alloy steel, hardness HRC64, high stability, wear resistance and easy combination.
Can be combined to any angle with interval 6 seconds after combination (6″, 12″, 18″, … , 360?).

3M 76622, Roloc Disc 777F, 36 YF-weight, TR, 1 in, Die R100N, 7000045618
3M 26120, PPS Series 2.0 Adapter, Type S28, 17.5 mm Female, 19 TPI
Thread, 7100135956
3M 54762, SandBlaster Quick Change Hub for Right Angle Grinder 9675, 4.5 in, 7010301728 