Not compatible with the 3M version which looks exactly the same but has a much better seal. Sometimes it was difficult to get a proper seal with the 3M filter (aqua pure AP801). The filter elements are identical, but the threads are different. Due to the high iron content in well water, I use a Pentek filter element. The zero water meter shows 88 TDS but I don't know how much iron I have in PPM. Revain shipped mine with no packing material, so one of the filter holders inside the manifold was…