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?).

Dynabrade 78581 1/4" Dia. x 1" W x 1/8" Center Hole, 120 Grit, 100/pack
3M 26120, PPS Series 2.0 Adapter, Type S28, 17.5 mm Female, 19 TPI
Thread, 7100135956
3M 54765, SandBlaster Right Angle Grinder Multi-Layer Disc 9679 60G 4-1/2 inch, 7010339877 