Based on a search, "pack 1125.rar" appears to be a specific, likely compressed, file often associated with custom content, mods, or specialized asset collections in user forums or file-sharing sites.
Files named this way are often organized by number to allow users to download specific, sequential "packs" or updates for a larger collection [Source: Custom content repositories]. pack 1125.rar
Always scan .rar files with updated antivirus software before extracting, as files from community sites can pose security risks. Based on a search, "pack 1125