Like frogmats...

[tommo666]

Almost like frogmats but less expensive. From Poundland size - 15in x 9.5 inch

[keith157]

I have loads of them, but even the really expensive ones don't like too much heat, I have seen pics of them used to wrap joints Etc for low and slow, but I wouldn't want to try them on a hot and fast grill for prawns etc. They wouldn't stand the high temps.