I have an oddball dimension because my dimensions are accurate, versus the filters at the store which are usually larger than their actual label. Recently they stopped stocking that size and they don't even order them anymore. Which left me in a bind, I'm glad I found Fiilterby, I was surprised at how many dimensions were available, I will be going back 1st long as I have this furnace and I've already recommended them to a couple of people verbally.