Product review (3 stars): Seems Effective, Price OK, but Recycling Program not Bundled
Works fine in our decade-old twist-style Whirlpool (take the cap off, dummy).

Be sure to wash water through it before using the filter for its intended purpose, as noted in the instructions.

I have no way to test effectiveness of the filter (there's no detectable taste, which is good), so I must declare it to be acceptable.

What isn't acceptable is that the company doesn't provide a convenient return method for recycling this obviously-suitable-for-recycling item. It's offered through a separate program as far as I can determine.