Nancy Schwindt told me that if I didn't already sell this item, I should. I always listen to Nancy because she is really smart and one of the best homekeepers I know. You put this on the bottom of your oven and the next time a pie boils over or a wad of cheese seeps out of a calzone it falls onto this mat. The offending ooze will dry up and turn into a dark pile of ash. When the oven is cool, you pull the mat out, rinse it in the sink and pop it back into your oven. Nancy is so right about this oven liner. It's a huge timesaver. They make it for toaster ovens, too. For use in electric ovens only. It measures 30" x 16 1/4" and will fit up to a 30" oven but can be trimmed to fit any size oven. MADE IN THE USA.