Product review (1 stars): If you change something, don't maintain it's the same.....
Apparently Whirlpool, without notifying long held customers, changed, slightly, the configuration of housing inside the refrigerator that the filter nests into so that the notches that marry the filter to the housing no longer fit the housing. Therefore these filters that matched the number of the product that I have used over several years, even though they match, the filter doesn't match now.  Not  pleased. So we had to pay nearly $300. to an authorized Whirlpool repair shop to replace the housing so that any new filters, with the same number, now, apparently, will fit the newly installed housing.  How fun is that?
These filters were returned because I thought they were wrong, but it was the housing instead, so I don't know if the filters were okay.