: The double .7z.7z suggests the file was compressed, and then the resulting archive was compressed a second time before being split.
: Download and install the 7-Zip archiver or a similar tool like Unzip One . BVV-15_R.7z.7z.001
: Right-click on the .001 file and select 7-Zip > Extract Here . : The double
: Ensure every numbered part of the archive is downloaded to the same directory. BVV-15_R.7z.7z.001