Update: About 30 minutes after I wrote my review, I get a call back from this company. I'm still disappointed in their service but I did get an education on filters. Apparently I needed (and expected) a Reverse Osmosis filter, which this filter is not. So I ordered something that's not useful to me. I wish the product details on the Amazon site were more clear for people like me who are not that knowledge on water filters. I changed my review from a 1 to a 3 but for me the product is useless...but maybe not for you.
The install of the filter was very easy but it works like crap and I've attempted about 6 times to contact the mfr. I use the Zero Water pitcher/filter system (see pic) that I got on Amazon that is freaking awesome! But we drink a LOT of water so we're constantly filling the pitcher. The Zero Water comes with a TDS water purity measurement device as shown in my photo. ZW say to not really drink water over a 50 TDS. Our tap comes out around 70 to 80. Our old filer on our refrigerator was at 67. So I bought this filter to hopefully get below 50 TDS. After installing it, the device was showing 187!!! Holy crap that's really bad water. I ran about 20 gallons or more through the refrigerator in the hopes of getting this contamination to drop. As you can see in the pic, I had it down to 104 and today its about 72...so still above the recommended drinking level and about the same as our regular tap water. So the filter I bought IL-20K from Watts here on Amazon is crap! And I can't get the company to answer the phone or call me back from the numerous messages I've left. Now its too late to return on Amazon. Based on my one experience with this filter, I absolutely do NOT recommend it.