: The .7z.001 extension indicates a 7-Zip multi-part volume.

Based on the naming convention, here are the details regarding this file: File Type and Extraction

The "SS-Mil" prefix is commonly associated with specific Japanese adult video (JAV) labels or release groups (often "Sky Angel" or "Milky" series). The number refers to the specific volume or episode in that series.

The file is the first part of a split compressed archive, likely containing video content. To open or extract it, you generally need all the numbered parts (e.g., .001 , .002 , .003 ) saved in the same folder.

: If any parts are missing from the sequence, the extraction will fail with a "Data Error" or "Unexpected end of archive." Content Context

: Use a utility like 7-Zip (Windows) or Keka/The Unarchiver (macOS). You must right-click on the .001 file specifically to start the extraction process; the software will automatically "stitch" the remaining parts together to recreate the original file.