Product review (1 stars): Is this really filtering anything?
I measured the ppm of tap water, this filter, GM's official MWF water filter, and Brita water filter with HM Digital TDS-EZ Water Quality TDS Tester.

Results:
Tap water 155
GM Compatible filter 154
GM filter 154
Brita water filter 84

So I'm not going to use the refrigerator water or ice for consumption. Brita all the way.