Thanks for posting.
The correct battery part number for the Inspiron 15 5559 is: FJCY5
I would be very leery of that seller - the price is far too low. It's either old stock (remember a battery's clock starts ticking the day it's made -- if it's a year old, it may have half its life behind it before you even start using it) -- and the warranty isn't particularly good either -- or, it's a battery that's had its cells replaced.
Thanks for posting that advertisement. I would be very leery of that particular battery due to the things ejn has mentioned, plus the fact that this is not an OEM battery. See the disclaimer? Some of these Chinese re-manufactured batteries have allegedly caused fires and damage.
Hello! I'm having a hard time finding a replacement battery for my inspiron 15 5559. Based on the battery type it says M5Y1K. Is the battery sold in Amazon correct for my laptop? Thank you for the answer!