"Manufactured from corrosion-resistant steel (17-4 AMS 5643 Cond A), this item undergoes heat treatment per MIL-H-6875 to Condition H1025 with a Rockwell C hardness of 35-42. The finish involves passivation according to MIL-STD-171, Class 5.4.1 and black oxide treatment as per MIL-C-13924, Class 4. Dimensions are 0.51 inches in diameter and 0.13 inches deep, featuring two 56 UNC-2B holes."