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 4120-18N, METRIC THREAD RING GAGE, NO GO, M18x2.5, 6928640341816
3M 34425, General Purpose Sanding Sponge CP041-3PK, Single Angle, 2-7/8 in x 4-7/8 in x 1 in, Medium, 7100175218, 3/pack 