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?).

Insize 4120-12N, METRIC THREAD RING GAGE, NO GO, M12x1.75, 6928640341786
3M 26105, PPS Series 2.0 Adapter, Type S21, 14 mm Female, 1.0 mm
Thread, 7100135829
3M 07054, General Purpose Sanding Sponge CP041-12-CC, Single Angle, 2-7/8 in x 4-7/8 in x 1 in, Medium, 7100101246 