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 94990 1/4" Female Composite-Style Coupler with 1/4" Male Plug Assembly
3M 87053, Cubitron II Stikit Film Disc 775L, 150+, 6 in x NH, Linered w/Tab, Die 600Z, 7100075207, 250 per case
3M 26110, PPS Series 2.0 Adapter, Type S24, 1/4 Female, R-Angle 18
Thread NPS, Side Cup Mount, 7100135940 
