Product review (4 stars): or bad seal, the second o-ring would stop your home ...
Although the product works well and I find it to be a suitable replacement for the OEM cartridges, I originally purchased this item thinking there were two o-rings at the head of the cartridge as shown in the pictures.  However, the actual product only has one o-ring so the pictures for this item are mis-leading so that is why I knocked off one star.  That being said, I have had no issues with it and have used others with single o-rings without any issues as well.  OEM from Samsung does have two o-rings which I guess in case of a leak, or bad seal, the second o-ring would stop your home from being flooded.