I get the perfect size, hard to find, and the right filtration level, quickly. Far better than going through racks of filters at the big store. I have 5 units, 3 take a 2" filter.
I bought the size 24x36x1A and received a 24x36x1 which is actually smaller. due to that i can hear the filter fall down when the air cuts off. it also makes a whistle sound because it is not the right dimensions.