This recommendation relates to rigid precision coaxial lines and their associated precision connectors for instrumentation, to be used within the limits for temperature, humidity and pressure as given in the standard atmospheric conditions for testing in Publication 68-1, Part 1: General. Precision connectors can be of the hermaphroditic type, flange type or of the pin and socket type. This recommendation covers requirements for precision connectors mounted on rigid precision coaxial lines and gives mechanical data for coupling mechanism.