Product review (4 stars): (3-Pack) Duracraft Humidifier Replacement Filter AC-818 /
Filters fit, seem well made and perform as well as the 'science' or design permits.  What does that mean?  The 'wicking' action is overcome by the fan and the top 1/2 of the element dries out quickly.  The top 1/2 is the only opening from the back of the cabinet from which air is sucked in by the fan.  Thus, 'humidifying action' is quickly limited unless the element is reversed, upside to down, down to up which defeats much of the 'automatic' intent of a built-in humidistat self-regulating unit; it needs regular if not constant attention.  The element performs well in its limited designed and implemented humidifier - it is not the fault of the element.