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™ 72013, Adapter 529-04-50, 110-120 VAC, 7000131705, 1 EA/Case
3M 11419, Roloc Disc 361F, P240 XF-weight, TR, 2 in, Die R200P, 7000045105
3M 22405, Roloc Disc 361F, P100 YF-weight, TR, 3 in, Die R300V, 7000045102
3M 41597, Polyurethane Adhesive Sealant 560, Black, 310 mL Cartridge, 7100005901, 12/Case
3M 07053, General Purpose Sanding Sponge CP-040NA, Single Angle, 2-7/8 in x 4-7/8 in x 1 in, Fine, 7100110752 
