The Siemens 6SL3566-4NA00-0GA0 is a SINAMICS G115D Quickon nut that provides the mechanical and electrical connection for 400 V AC supply in a Quickon wiring system. This is the specific nut for the drive's power input — not a cable, not a connector body, but the threaded coupling that secures the Quickon plug to the drive housing. If you are building a G115D panel and the power connector kit is missing this nut, the line stops here.
Panel integration note
The Quickon nut is a small part — 165 x 117 x 55 mm packaged — but it is the single point of failure for the AC input connection on a G115D drive. In a panel build, torque it to the drive's Quickon receptacle before dressing the cable; the nut seals the connection against vibration and moisture ingress typical of a washdown or outdoor enclosure. The drive itself is IP66-rated, and the nut maintains that seal only if the O-ring is seated and the nut is tightened to the specified torque (not listed here, but available in the G115D mounting instructions).