Frost King ES1550/6 Window Air Conditioner Electrostatic Filter, 13.5" x 24" x 1/4", White

As a filter it does its job reasonably well, but it suffers sufficiently even in mild washing that I have significant doubts about its life-expectancy.

Placed in front of the air intake of the factory filter and taped in place, this filter does a great job of removing allergens that simply flow through the filter system otherwise. Additionally, this double filtration extends the life of the evaporator by reducing clogging. Placing basic foam filters over the air intakes on the outside of the unit (for the condenser) greatly keeps it from becoming clogged also (probably something the manufacturer doesn't want you to know). Simply take off all filters and clean regularly...

This filter seems to be a good material and was trimable for my application, will take some time 1 month at least to see if it works any better.

great filter