Product review (4 stars): It should have some kind of gauge of how many gallons passed through it and recommend the replacement intervals
Works as advertised, but I don't know about the "replace every 6mo." part, since I hardly use the water/ice dispenser of the fridge, esp. during winter months.  It should have some kind of gauge of how many gallons passed through it and recommend the replacement intervals, on second thought, forget it, it would just cost twice as much!