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 2197, LARGE RANGE DIGITAL RADIUS GAGE, R1(4-590"/100-1500mm), R2(4-590"/100-1500mm), 697409778087
3M 17083, Versaflo Hood with Integrated Head Suspension, S-433L-5, Medium/Large, 7000029981, 5 EA/Case
Dynabrade 53270 7" (180 mm) Dia. Right-Angle Disc Sander 