I have now had three of these filters to screw onto my Clearly Filtered pitcher. The first one worked amazing and lasted a very very very long time, in fact I forgot to change it out and was using it for a year. Even that old, the difference in taste between the tapwater and the filtered water was very apparent. So I just ordered a replacement, but the replacement actually did not screw on properly. I wrote an email to the seller and they immediately sent me a replacement and told me to keep the defective one. The replacement screwed on perfectly and now my water tastes completely pure. They mentioned there was a batch that ended up defective but they were so nice and took care of it so fast I can’t really take any points off. And I have not laboratory tested my water but it tastes as pure as air. Liquid air. I’m expecting it to last a long time, btw when they start to get old the water drips down more slowly.