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 29825, Sanding Screen, 60 Grit, 20 in x NH, 7100160253
3M 22396, Roloc Disc 361F, 36 YF-weight, TR, 1-1/2 in, Die R150S, 7000045091
Insize 2307-1R, REVERSE READING DIAL INDICATOR, 1", lug back, 6928640396649
3M Super Abrasives Roloc Disc, 2" Type-R, Medium AO High Strength, Box of 50 