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 03140, General Purpose Sanding Sponge CP041-6P, Single Angle, 2-7/8 in x 4-7/8 in x 1 in, Medium, 7100101537, 6/pack
Insize 6140, DEPTH BASE ATTACHMENT, suitable for calipers with beam width (w) .630", 6928640303579
3M 55694, Stikit Film Disc w/Tab 375L, P180, 5 in x NH, Die 500X, 7100106554, 250 per case
3M 26017, PPS Series 2.0 Adapter, Type S10, 1/4 Female, R-Angle 19
Thread BSP for Side Cup Mount, 7100135927 