I called purolator and asked for some beta and flow specs on 2 particular filters and the guy gave me engineering's number. I called it, guy was sketchy on the flow. he didn't really answer my Question. he said... 3-6gpm, i've seen them up to 17gpm. Kind of a politicians answer. he said the beta ratio for all the filters were the same b/c they all use the same media. I'm trying to figure out how much the PL10241 and PL20195 flow and beta ratios for them.