This Standard is used by all AIMD NDI shops shore-based and shipboard intermediate maintenance activities for calibrating eddy current units prior to inspection. The Standard is a three (3) plate assembly measuring 4″ x 7″ x .875″. Contains twenty (20) fastener holes with diameters from 0.156 to 0.750″, two (2) screw holes, and two (2) dowel pins holes. Standard also contains a total of 71 EDM notches in various locations. Notch depth and length may vary. Width is 0.004″ for all notches. Manufactured in accordance with U.S.A.F. Tech Order 33B-1-1. Figure 4-50. Kit P/N is NRK-3AST and consists of (1) Aluminium, P/N NRK-3A, 7075-T651 top and middle layer; (1) Steel, P/N NRK-3S, 4340 alloy all three layers, and (1) Titanium, P/N NRK-3T, 6AI-4V alloy all three layers.