MIL-STD-1531A, DEPARTMENT OF DEFENSE INTERFACE STANDARD: INSERT ARRANGEMENTS FOR MIL-C-83733 RACK TO PANEL CONNECTORS, SHELL SIZE A (25 MAR 1988)., This standard covers insert arrangements for use with MIL-C-83733 rack to panel connectors, shell size A. It is used to control the dimensions and configuration of insert patterns and the contact sizes.