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 77762 4-1/2" Dia. x 7/8" Center Hole, 40 Grit, Type 27, Ceramic DynaCut Flap Disc, 10/pack
3M 45029, Diamond Grade Digital Reflective Sheeting 3924SUDS, Fluorescent Orange, 30 in x 50 yd, 1 Roll/Case, 7100282407
3M 26110, PPS Series 2.0 Adapter, Type S24, 1/4 Female, R-Angle 18
Thread NPS, Side Cup Mount, 7100135940 