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 45097, Roloc Disc Pad TR, Extra Hard 2 in 1/4-20 Internal, 7000045284
3M 82975, Roloc D/F Cool Running Disc Pad TR, 3 in 1/4-20 Internal, 7010309116
3M 45179, Roloc Disc Pad TR, Medium 4 in 1/4-20 Internal, 7000045281
3M 83980, Roloc Disc Pad TR, Extra Hard 4 in 5/8 -11 Internal, 7000119300
Insize 5022, 2-PIECE MEASURING TOOL SET, 6928640321290 