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 65489, Pro Grade Precision Ultra Durable Universal Hole Sanding Disc, DUH5120TRI-10T, 5 IN x UH, 120, 7100202877, 10 per pack
3M 92250, Extra Large Single Angle Sanding Sponge 910PSA-12-CC, 2-7/8 in x 8 in x 1 in Fine, 7100101547
3M 26017, PPS Series 2.0 Adapter, Type S10, 1/4 Female, R-Angle 19
Thread BSP for Side Cup Mount, 7100135927 
