u/Fluffleblow

I'm looking at both of these filters and not sure which one to go with. I like that the WF511 comes with 2 pitchers at 1.5L, as I intend to keep one in the fridge. The WF112 has one 1.1L pitcher, so I'd be purchasing an additional one for $20. The main thing I don't understand is the PPC filter on the WF511. What exactly is it doing that justifies the price difference between two models?

WF511 - $300

WF112 - $170

I also welcome any additional info that will make my decision easier.