Product review (1 stars): Not worth the trouble
As numerous other reviewers have noted, this filter is only NSF 42 certified and not NSF 53 certified.  Given that the municipal water where I live is pretty good this is not a huge concern, but worth noting.  More importantly is that when I removed the filter, the filter head became misaligned.  Despite watching online videos on how to fix/reverse the problem, I was unable to do so, and I eventually had to call an appliance repair man to come and replace the filter head.  So, I would urge you to beware of using this product.  In the best case, you will save some money on an inferior filter (NSF 42 vs NSF 42 + NSF 53). In the worst case, you will need to pay a repair man to fix your refrigerator.