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 97571 1/2" NPT Male Safety Coupler
Dynabrade 98269 1/2" Female Coupler
Dynabrade 94993 1/4" Male Composite-Style Coupler with 1/4" Female Plug Assembly
3M 07053, General Purpose Sanding Sponge CP040-12-CC, Single Angle, 2-7/8 in x 4-7/8 in x 1 in, Fine, 7100101245 
