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 27259, Ultra Durable 5 inch Power Sanding Discs, Universal Hole, 120 grit, 7100188461, 5 per pack
3M 45100, Roloc Disc Pad TR, Hard 1-1/2 in 1/4-20 Internal, 7000045286
3M 7493, SCOTCH-BRITE SURFACE CONDITIONING DISC PAD HOLDER 7493, 3 IN DIA, 7010309651
3M 20967, Portable Utility Cloth Roll 314D, P240 J-weight, 1 in x 20 yd, 7010290604
3M 37024, Extra Large Drywall Sanding Sponge 910-DDA, Dual Angle, 2-1/2 in x 8 in x 1 in, Fine, 7010375249 