IEC 61169-66:2021 provides information and rules for the preparation of detail specifications (DS) for series 2,2-5 RF coaxial connectors with quick-lock- or screw coupling, characteristic impedance 50 Ω, for operating frequencies up to 6 GHz. Typical use is in wireless telecommunication systems. It describes mating face dimensions for general purpose connectors - grade 2, gauging information and tests selected from IEC 61169-1, applicable to all detail specifications relating to series 2,2-5 RF connectors. This specification indicates recommended performance characteristics to be considered when writing a detail specification and it covers test schedules and inspection requirements for assessment levels M and H.