External Hard Drive issues

I am looking to pick up an External Hard Drive by $183 😉

But looking at these options... I can't quite wrap my head around the actual difference between:

External Hard Drive Western Digital password 2.5" 320GB USB Element => $165

and

External Hard Drive Seagate 3.5" 500GB Airy 69080 => $166

In terms of reputation... and hopefully quality too... though I'd expect it to be 😁

Plus, it's just another 3.5" drive, which basically means it's cheaper anyway...

It seems this memory module is categorized under some sort of exclusive tier of hard drives... whereas this Western Digital unit is just listed under standard HDDs... which led me to believe that specific memory was something else entirely 🤷 😁