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 11845, 3M Cubitron 3 Flap Disc 1169F, 80+, T29-Conical Quick Change, 7 in x 5/8 in-11, 5 ea/Case, 7100380504
3M 86804, Cubitron II Stikit Film Disc 775L, 80+, 6 in x NH, Linered w/Tab, Die 600Z, 7100045866, 250 per case 