Purney,

Wix has a great cross reference site. I went there and input a bunch of your numbers and numbers from previous posts. They indicate that many of the filter cartridges mentioned are 4.094 OD X 5.007 high. The number littlebuddie just quoted comes right back to those dimensions. I think the filter numbering system has been around for so long that it is funked up. The same filter might have two different numbers for two different applications...I'll throw in the towel too!

Stuart