This specification covers three series of environment resisting@ circular@ miniature electrical connectors (plugs and receptacles) with removable crimp and/or nonremovable solder contacts@ and accessories. The connectors are only recommended for replacement and are not specified for aircraft applications (see AS50881). Series Description The connectors are identified as series 1@ 2@ or 3@ and are designed to provide contact protection during mating and include the following features: Series 1 - Push-pull coupling@ single key solder type nonremovable contacts (-55 to +125 ??. Series 2 - Rack and panel or push-pull coupling@ single key@ removable front release crimp contacts (-55 to +175 ??. Series 3 - Rack and panel@ single key or push-pull coupling@ five keys@ removable rear release crimp contacts (-55 to +175 ??and +200 ??.