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 77197, Scotch-Brite™ Roloc™ Deburr and Finish PRO Unitized Wheel,TR, 3 in x 1/8 in x NH, 8C CRS+, 7100109130, 40/box
Insize 2197, LARGE RANGE DIGITAL RADIUS GAGE, R1(4-590"/100-1500mm), R2(4-590"/100-1500mm), 697409778087
Dynabrade 79127 3/4" W x 18" L 120 Grit DynaCut Premium Ceramic Belt, 50/pack
Dynabrade 78587 1/4" Dia. x 2" W x 1/8" Center Hole, 60 Grit, 100/pack
3M 05444, Stikit Hand File Board, 2-3/4 in x 16 in, 7000045763
3M 91004, Drywall Sanding Sponge CP-042-4PK, Single Angle, 4-7/8 in x 2-7/8 in x 1 in, Fine, 7100111452, 4/pack 