Need help buying/setting up subwoofer

So today I bought a soundbar and it sounds pretty good for music in my opinion, it just doesnt pack as much bass as I want it to, so I would like a subwoofer.

I was thinking of getting this one:

Does it seem like a decent one?

Also, my soundbar has a single rca jack that says "SUB OUT", but on the subwoofer it has 2 cables to plug in (left and right), would it work fine if i got a splitter?

Like a 1 male to 2 female rca splittler, so i plug the male end into the sound bar, then i plug normal red and white rca cables into the 2 female ends

Thanks for any help

You can use a splitter, but you don't have to. This is from the manual for the PSW10:

NOTE: The PSW10 subwoofer does not have an LFE input. Instead, use either the
L or R Line input (another hookup option is to use a Y-split cable and connect both
L and R Line inputs). After you make this Sub Out connection, turn the "Low Pass"
filter fully clockwise. This will in effect create an LFE input.

As for whether it's decent or not, Polk is pretty good stuff and that sub is well rated.

Ah ok, thanks for the help and suggestions i will buy this one for sure!