Product review (3 stars): Flawed installation markings?
This seems to be working, although the "lock" icon on the label below the raised marker line on the side do not end up at the mark on the refrigerator's receiving port.  Not even close.  It also did not take a quarter turn to lock.  I'd say it moved abou 1/2inch to the right to seat.

The locking pieces are stepped-plastic parts on either side.  Either one can be in front.  The unit won't insert in any other position.  I can only assume they messed up the specs on positioning the markers during manufacture.

The water and ice dispatch so I'm guessing they are working.  How would one even know if the things are filled with proper filtering stuff?  My local Sears quit selling these right after I bought the fridge.  Bad Sears!

My only wish is that they would figure out an easier, faster way to flush 2.5 gallons through these filters after installation.  I'm considering a short hose under the outlet, duct tape on the control and a bucket on the floor next time.  (only half kidding)