The filters that I have been using, all from different manufacturers, only have 1 large O ring and 2 very small O rings in the kits. The 2 small rings go on the bottom part of the plastic cap and the large O ring goes to the top to make the seal. There is another O ring near the top of the cap which goes between the threaded part but that ring doesn't come with the new kit. I did source one of those locally and fitted it. I just think that the O rings that come with the kits aren't thick enough to make a proper seal. Thanks for the advice.