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 10476 Housing
Dynabrade 58041 11" Dia. Two-Hand Gear-Driven Sander, Central Vacuum, .45 HP, 900 RPM, Hook-Face Pad
Dynabrade 51345 2" (51 mm) Dia. Locking-Type Disc Pad, Medium Density, 3/8"-24 Thread
Dynabrade 10843 DynaPen Reciprocating Tool, 14,000 SPM, 1/8" Collet
Dynabrade 56873 3-1/2" Dia. Self-Generated Vacuum Dynorbital Supreme Random Orbital Sander, 3/8" Orbit
Dynabrade 79840 DynaBolt AO 4" x 1/4" x 3/8" T27 Grinding Wheel, Box of 10 Discs
Dynabrade 51078 Bearing
Dynabrade 01797 Exhaust Cover 