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?).

Dynabrade 78596 3/8" Dia. x 1-1/2" W x 1/8" Center Hole, 120 Grit, 100/pack
Insize 7231, SCRIBER, 6928640320071
Dynabrade 78423 4-1/2" Dia. x 3/8" Very Fine DynaBrite Surface Conditioning Disc, 25/pack
3M 92250, Extra Large Single Angle Sanding Sponge 910PSA-12-CC, 2-7/8 in x 8 in x 1 in Fine, 7100101547 