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 6313-1H2, SETTING RING, 1/2" dia., 6928640330407
3M 65489, Pro Grade Precision Ultra Durable Universal Hole Sanding Disc, DUH5120TRI-10T, 5 IN x UH, 120, 7100202877, 10 per pack
3M 91004, Drywall Sanding Sponge CP-042-4PK, Single Angle, 4-7/8 in x 2-7/8 in x 1 in, Fine, 7100111452, 4/pack 