Get a 3rd party casing, cheap one price start from 30+ IINM.

Basically a external HDD is just a normal laptop 2.5" HDD slapped with SATA to USB adapter and put in a case. 3rd party case or even the adapter along will work just as well.

But one thing to note, WD is an exclusion to my statement above, they purposely make their external HDD with 2.5" HDD of their own propriety connector, so if it broken down you really need to contact them back to fix it.