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 19087, 1100 Probed Test Earplugs 393-2010-50, 10 Pair/Bag, 5 Bags/Case, 50 Pair/Case, 7000002409
3M 85492, Scotch Foil Tape 3311-10A, 2.0 in x 10 yd (50.8 mm x 9,1 m), 7010383663
3M 97419, Aluminum Foil Tape 3380, Silver, 48 mm x 45 m, 3.25 mil, 7000049613 