Difference between RED NAS and Mobile RED NAS

Hi all, please can anybody explain me difference between :
WD Red 6TB - WD60EFAX
and
WD Red 6TB - MOBILE NAS drive (attached photo)

Very thanks Vaclav

Looking at Western Digital Product site (link below) the first obvious difference is the physical size.

The “Mobile NAS” is 2.5" Inch and the other is 3.5" Inch

For other differences … check the specs on the link above.

Hi, very thanks for answer ! Maybe it was problem with picture on czech eshop …
it should be WD60EFAX

Can anybody confirm than WD60EFAX is same as WD60EFRX ?
(lenovo px6-300d have only WD60EFRX in compatibility list,
but EFRX is sold out)

Thanks for answer ! Vaclav