The positions of anvil and penetrator can be reversed for internal-surface testing.     Test specimens Traceable test specimens are essential for getting good tests. We sell only certified test specimens traceable to national standards.   Anvils The correct anvil helps ensure valid readings by making sure work does not move during load buildup. Anvils are interchangeable.   A - Raised flat for thin stock B - Convex for tube stock C - Round for larger round stock D - Vee for small round stock E - Standard Flat stock anvil       Penetrators For each scale, you need the correct penetrator. They are interchangeable. Diamond Penetrators with 120° cone and spherical point.    Standard - for Standard Scales A, C, D    Superficial - for Superficial Scale N Ball Penetrators    1/16" - for B, F, G, and T Scales    1/8"   - for E, H, L, and W Scales    1/4"   - for L, M, P, and Y Scales    1/2"   - for R, S, V, and Y Scales         Bench Stand Cast iron for solid support. Holds tester at a convenient angle, freeing hands for ease of use. Inner fibre sleeve won't scuff tester handle. Weight: 11 lb.