Need a disk for a RAID array, not clear how to read the model number

Hello I need to replace a faulty WD red HDD that is part of a RAID array (four disks overall), so I guess the model MUST be the very same as the other disks’.
Now I can see from the diagnostics of the RAID appliance that disk’s model is WD40EFRX-68WT0N0 and indeed I could find some WD red HDD on sale, but each one shows up as just WD40EFRX, lacking the 68WT0N0 suffix: does it matter somehow? Or I can assume that buying a WD40EFRX disk is enough to be sure it will fit seamlessly into the RAID array?

Thanks everyone for hints and suggestions.

Hello,

Please refer to the following KBA article: http://support-en.wd.com/app/answers/detail/a_id/25488/

Hello, thanks for pointing me to some KBA resources. Anyway, on the article you provided I couldn’t find any helpful info regarding my problem. What I need to know is what HDD model must I search for, in order to safely replace it in my RAID array (by safely I mean without any compatibility issues). Is ANY WD40EFRX drive fit for a safe replacement or do I have to buy a WD40EFRX-68WT0N0 (whatever the suffix 68WT0N0 stands for) in order to make sure there will be 100% compatibility with the other HDD drives of the array?

thanks again for your help