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

Dynabrade 93243 8" Dia. x 1/2" Center Hole, 80 Grit, A/O, Arbor-Mount Sanding Star
Dynabrade 78703 3/4" x 3-48 Female Center Thread, Coarse, Dynabrite Surface Conditioning Eyelet Star, 50/pack 
