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 74800, Cushion-Mount Plus Plate Mounting Tape E1820H, Blue, 18 in x 25 yd, 20 mil, 7100021816
Dynabrade 13509 Dynastraight Finishing Tool, Rear Exhaust, 6,000 RPM, 5/8" (16 mm) or 1" (25 mm) Dia. Arbor
3M 14211, Roloc Disc Pad TS and TSM, Medium 2 in 1/4-20 Internal, 7000045283 