Product review (1 stars): Unusable in less than 2 weeks
After using this filter for about one week it began "slump" over, after two weeks it was unusable. It was so slumped over that it blocked the air flow of the humidifier. This filter has absolutely no structure to it after it gets wet. Buy at your own risk.

Fortunately, Amazon accepted the returns (I purchased two, one used and one still in the box) with no questions asked. Thank you Amazon.