4 Models - Inch and Metric, Turning and Grinding. Made of Solid Nickel.
Furnished in attractive vinyl case with instructions. Each model has 10 specimens: 5 each Internal Diameter (concave) and 5 each outside Diameter (convex).
10 Specimens - Shows ID and OD
5 each ID (concave) 16,32,63,125 and 250 Ra
5 each OD (convex) 16,32,63,125 and 250 Ra