I bought a PA 631 air cleaner element thinking it would fit a four barrel pancake air cleaner, well it doesn't. I will ship it to anyone in the lower 48 states that will send me $20. That can be a money order, personal check, or a twenty dollar bill folded up in a piece of paper and sent to me in an envelope. (Remember when we used to do that all the time?) This air cleaner is new and usually cost around $40 delivered, so this is a half price opportunity for those of you with 2x4 stock air cleaners. At least I think that is what if fits. If you live near me in Lakeport, CA, it is free if you pick it up at my place.