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 65487, Pro Grade Precision Ultra Durable Universal Hole Sanding Disc, DUH560TRI-10T, 5 IN x UH, 60, 7100202913, 10 per pack
Insize 1120-150A, ELECTRONIC INSIDE GROOVE CALIPER, 22-150mm, 6928640302220
3M 34349, Hookit Flexible Abrasive Foam Pad, 7000045570
3M 37024, Extra Large Drywall Sanding Sponge 910-DDA, Dual Angle, 2-1/2 in x 8 in x 1 in, Fine, 7010375249
Dynabrade 97570 1/2" NPT Female Safety Coupler
Dynabrade 15420 Dynafile III Abrasive Belt Tool
3M 03126, General Purpose Sanding Sponge CP040-6P, Single Angle, 2-7/8 in x 4-7/8 in x 1 in, Fine, 7100101532, 6/pack 