One more thing to note, with age and after the washer bag has been used, they seem to shrink. The new bags, early and late service, all measure approximately 10"x10" and all the used samples I have and seen seem to be approximately 3/4" to 1" difference, from the nos samples, all the way around. My guess would be because of the cloth material on the backside that would make them shrink in addition to the heat of the engine. With age and use they become somewhat distorted.