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 26053, PPS Series 2.0 Adapter, Type S14, 7/16 Male, 14 Thread UNC, 7100135932
Insize 3352-25AWL, HIGH PRECISION DIGITAL BLADE MICROMETERS/SNAP GAGE (built-in wireless), 0-25mm/0-1", .0002mm/.00001", 6940561982169
3M 37024, Extra Large Drywall Sanding Sponge 910-DDA, Dual Angle, 2-1/2 in x 8 in x 1 in, Fine, 7010375249 