Which nr directory should I download, there are many different directories for nr database at ftp://ftp.ncbi.nih.gov/blast/db

Dear discussion board,

Which nr directory should I download?

1. nr.gz at ftp://ftp.ncbi.nih.gov/blast/db/FASTA/nr.gz
2. nr.00.tar.gz at ftp://ftp.ncbi.nih.gov/blast/db/nr.00.tar.gz
3. nr.02.tar.gz at ftp://ftp.ncbi.nih.gov/blast/db/nr.02.tar.gz
4. nr.03.tar.gz at ftp://ftp.ncbi.nih.gov/blast/db/nr.03.tar.gz
5. nr.04.tar.gz at ftp://ftp.ncbi.nih.gov/blast/db/nr.04.tar.gz
6. nr.05.tar.gz at ftp://ftp.ncbi.nih.gov/blast/db/nr.05.tar.gz
7. nr.tar.gz at ftp://zhanglab.ccmb.med.umich.edu/download/nr.tar.gz. I am not
able to use ftp from ftp://zhanglab.ccmb.med.umich.edu/download/nr.tar.gz

Do I also need to Download checksum files nr.xx.tar.gz.md5 files?
If possible please let me know among these nr files which nr files should I decompress in $libdir/nr?
Do I need to use ncbi blast tools to convert these files into any specific format?

Regards
Manish