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

3M 65488, Pro Grade Precision Ultra Durable Universal Hole Sanding Disc, DUH5100TRI-10I, 5 inch UH, 100, 7100202876, 10 per pack
Insize 4807, ANGLE GAGE SET, 6928640319341
Dynabrade 78596 3/8" Dia. x 1-1/2" W x 1/8" Center Hole, 120 Grit, 100/pack
3M 22394, Roloc Disc 361F, 50 YF-weight, TR, 3 in, Die R300V, 7000045096
Norton 66261199696 - 3" X 1/4" X 1/4" Vortex Rapid Blend Unified Wheel, 7AM U2305, 40 Each
Dynabrade 92119 1/4" W x 12" L 220 Grit A/O DynaCut Belt, 50/pack
3M 76790, Roloc Disc 361F, 60 YF-weight, TS, 2 in, Die RS200P, 7010300088
3M 97419, Aluminum Foil Tape 3380, Silver, 48 mm x 45 m, 3.25 mil, 7000049613 