headlight gasket. it is only on the bottom where the seal meets the bumper. it doesn't go around the whole perimeter of the light if i remember correctly. you could take the lights out and form a spacer to encircle the inside of the seal. this would push out on the seal and eliminate the gap. i replaced both of my seals a couple of years ago and had to transfer the spacer from the old seals onto the new. i used weatherstrip glue to keep the spacer in place. hope this helps.