Re: Dell Inspiron 5577 2.5" Sata drive bay size. 7mm or
The drive needs to be 2.5" 7 mm or slimmer. You also need a cable, bracket and screws (these will need to be ordered from Dell Spare Parts).
You can easily find a 1T drive brand-new (not refurbished) for around or less than the cost of that refurbished drive -- shop around.