Sorry!

PB = Pool Builder
SWG = Saltwater Generator.

You've probably heard of "saltwater pools". The SWG is what automatically generates the chlorine from the salt in the water so you don't have to add chlorine yourself.

Hope this helps! I am FAR from an expert, but have learned so much from the folks in here. We are waiting for our building permits, and hope to start building in the next two weeks.