Product review (5 stars): Works great, but do your homework...
It seems like Whirlpool discontinued whatever filter they used to have and this is the replacement. That said, the prices have really gone up, and I was looking for alternate sources. When checking out the reviews on this site, I noticed that there were a lot of complaints, which made me nervous. I've had a bad experience with a counterfeit purchase before (not a filter), and some of these reviews remind me of that situation.

At least one person on here stated that their new filter was as heavy as their old one. That's a problem, as the new filter shouldn't have any water in it. The old one should feel a lot heavier than the replacement.  I just installed mine yesterday. Contrary to others here, it went in easily and locked.  I flushed it with 3 gallons of water, and the flow is at the same rate I'm used to. Flushing purges the air and loose particles. My water tastes clean. Our municipal water is good, so I have no experience with making crappy water good, but for what we're using it for, it's great.  Our fridge dispenses 100% of our beverage water (SodaStream, regular drinking water, tea, coffee & other hot beverages, etc.).  Also, we use it for some of our cooking, like soups, vegetables or hot cereal. About the only thing we don't use it for is  filling the dog's dish and a cooking a huge pot of spaghetti.  We're 100% satisfied.  My review doesn't show verified purchase because I've been dealing with a filter specialty house instead. To all the 1 star reviewers, If you're having these problems, I'd be suspicious. Call PUR. Maybe they can tell you if you have a legit product.