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 85492, Scotch Foil Tape 3311-10A, 2.0 in x 10 yd (50.8 mm x 9,1 m), 7010383663
3M 05020 Scotch-Brite Surface Conditioning Belt, 2 in x 60 in, A CRS, 7000120573
3M 54765, SandBlaster Right Angle Grinder Multi-Layer Disc 9679 60G 4-1/2 inch, 7010339877 