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 65488, Pro Grade Precision Ultra Durable Universal Hole Sanding Disc, DUH5100TRI-10I, 5 inch UH, 100, 7100202876, 10 per pack
Insize 0131-A120, LIGHT METER, 0.01~19.99FC, 0.1~199.9FC, 1~1999FC, 10~19990FC, 0.1~199.9Lux, 1~1999Lux, 10~19990Lux, 100~199900Lux, 6974029776557
Standard Abrasives 726001, A/O R8 Straight Precision Cartridge Roll, 1/2 in x 1-3/4 in x 1/4 in 100, 7100098772
3M 15041, Scotch Electrical Shielding Tape 24, 1 in x 15 ft (25 mm x 4,6 m), 7000031348
3M 11414, Roloc Disc 361F, P120 XF-weight, TR, 1 in, Die R100N, 7000045104 