Per the Crucial site here, the second drive can be a 2.5" SSD up to 2 TB.
I have a new Inspiron 24 5000 All In One, 512GB SSD boot drive, 16MB ram, on processor video. I wan't to add a second drive. Can the second drive be digital? I don't see it as an option; plenty of  HDD, but no SSD. I can't find any information on this. I'd go to Dell Support but they won't accomodate me unless I have the data (Tag No., etc.) of the computer, which I don't have memorized. Thanks in advance for the help.
ssd as second drive in 24 5400 AIO