Product review (5 stars): Fantastic Product - does what it says it will do!  How often do you find that?
These things are the BEST EVER!  You can actually place them under the heating element as long as the element has "feet" that keep the coil from direct contact with the oven floor.  They do not melt.  They do not shrink.  They do what they say they do.  I put them in both of my 21 year old ovens and they keep them looking great.  Also used the excess liner to line my toaster oven.  Love Love Love them!  Will buy them again - one day, when I get a new oven!