Product review (4 stars): Exact fit and no leaks
This item was an exact match to the factory installed original.  No need to shut off the water.  Just unscrew the old one and install the new one.  We don't use much ice or cold water, so we waited 12 months to change filters.  I cut open the used one and found a solid carbon sleeve inside a thick wall PVC shell.  No way to determine if it was "used up" or how much life it had remaining.  I have a photo but can't find a way to post it.