How do I get This Cartridge out to Check Leaky Tap?

[Larusso83]

Hi all,

Novice question but I how do get this cartridge out? The tap is leaking from the base (under the sink). I was going to see if replacing the o-rings does the trick but I can't seem to get the retainer nut thing out as there isn't a bolt on top of the tread like i've seen in every other tap and I don't want to force it.

Is it removed from the bottom when the whole tap comes off?

Thanks in advance!