little problem with Hard Disk Low Level Format Tool

[Jaroo]

Hi everybody,
I've just downloaded Hard Disk Low Level Format Tool because I'would like to format my WD740ADFD-00NLR1: the problem is that I've another identical hard disk (except for the serial number obviously) and I don't Know how to distinguish one from the other when I've to select which hd to format...
any ideas?

Thank you,

Jaroo

[Spildit]

First get MHDD and makea boot MHDD disk.
Remove the power from the drive that you don't want to format and test it to see if you have removed the power from the correct drive.
Boot from MHDD.
Issue the Secure Erase command.
Wait until the green Busy light turns off.