Product review (5 stars): Works fine.  Ridiculously overpriced, but fine.
These appear to be original equipment. They come without installation instructions, but if you were able to remove the old filter, you can certainly screw the new one in (and write the date on the front...some refrigerators don't have a 'change filter' reminder).  I bought this filter to replace the one in an older refrigerator in a house we bought; I didn't know how long the old one had been there.  What I decided after I bought this, though, and this is purely a personal decision, is that when it's time to replace this one, I'm just going to remove it and not replace it.  Here in Palm Springs, we have great tap water, and since I like the flavor right out of the tap, I can't see paying $42 for a filter I don't need.  And if you're wondering if your refrigerator/icemaker/drinking water will work without a filter installed, yes, it will; when you remove the filter, the water flow bypasses the hole it screwed into.