Product review (5 stars): Stopped a horrible knocking noise coming from our Samsung Refrigerator!
Thanks goodness for this product... we have had a Samsung refrigerator for about a year and a half.  All of a sudden when it would pull water from the line it would make a horribly loud knocking noise coming from the back of the machine.  Since we knew it was related to the water line, I thought I would first try changing the filter.  We have done so, and the noise stopped completely.

Oh!  And do not be alarmed if the first few cubes are dark grey (or black)... apparently this is normal.