-P
is a RAR (Roshal ARchive) file, which is a type of compressed archive. The ".part4" indicates it's part of a multi-part archive, suggesting the original file was too large to be sent or stored in one piece, so it was split into several parts. FC2-PPV-4505968.part4.rar
To view the content within FC2-PPV-4505968.part4.rar, you cannot simply open it in isolation. You must have all the preceding and succeeding parts (e.g., part1, part2, part3, etc.) located in the same folder. Download all parts associated with the ID 4505968. Use a program like WinRAR or 7-Zip. Right-click on Part 1 and select "Extract Here." -P is a RAR (Roshal ARchive) file, which