Measure radius of external arc, arc angle of measured surface should be larger than 90?
Resolution .0005″/0.01mm
Buttons: on/off, set, inch/mm, preset (+, -)
Automatic power off, move the digital unit to turn on power
Battery CR2032, Data outputMade of stainless steel
Supplied with pin gage for zero setting

Insize 5313-S407, 3D MANUAL ROTATION MICROSCOPE (WITH DISPLAY), 6940561981360
Dynabrade 78586 1/4" Dia. x 1-1/2" W x 1/8" Center Hole, 180 Grit, 100/pack
3M 24049, Wetordry Cloth Disc 281W, P1000 YF-weight, 8 in x NH, Die 800JM, 7000045052
3M 15041, Scotch Electrical Shielding Tape 24, 1 in x 15 ft (25 mm x 4,6 m), 7000031348
3M 19769, Utility Cloth Sheet 314D, 9 in x 11 in P150 J-weight, 7000000357
Dynabrade 95684 1/4" Male Coupler
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
3M 27468, EMI Copper Foil Shielding Tape 1181, 1 in x 18 yd (25,40 mm x 16,5 m), 7000132169 