Product review (4 stars): Tight fit. Good results.
Be careful with these folks. I have to use a large wrench to twist them into place. The wrench gives me too much leverage. This last time I twisted too far. The filter popped out partially and water gushed everywhere. I shut off the water supply and thought I had broken the filter holder/valve mechanism. I disassembled it, put it back together and everything is fine.  Lesson:  if you have to force the filter in stop when you hear the water gushing into the filter.  They are a great value and work well.