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 27252, Ultra Durable 5 inch Power Sanding Discs, Universal Hole, 220 grit, 7100188458, 10 per pack
3M 11419, Roloc Disc 361F, P240 XF-weight, TR, 2 in, Die R200P, 7000045105
3M 16124, PPS Type H/O Pressure Cup, Large (28 fl oz, 828 mL), 7000119668
3M 10455, Cloth Sheet 481W, 220, 9 in x 11 in, 7010294811
3M 22395, Roloc Disc 361F, 60 YF-weight, TR, 3 in, Die R300V, 7000045098
3M 06466, Cut & Grind Wheel, Type 27, 6 in x 1/8 in x 5/8"-11, Quick Change, 7100218055, 20 per case
3M 20913, PSA Cloth Disc 348D, 36 X-weight, 2 in x NH, Die 200P, 7000118919
3M 26583, Accuspray Refill Pack for PPS Series 2.0, Green, 1.3 mm, 7100152953 