The post about the FL-784 got me thinking-
Using the Wix equivalent 51742, I looked up the Beta#'s
2/20=24/44
Looking at other filters that had a Beta 2/20=xx/xx, typically had a Nominal Micron Size of 19.
I therefore ASSumed, subtracting 1 micron from the Beta 2/XX=..., would result in the...