I came across this Brookfield Insualator. Did some research and learned I have no clue about the CD #s but found that some of these have errors. I will post more pictures but in this one you can see the embossing from the inside. On top it looks like "11." the second 1 looks funky. When I flipped it looks like "1L" or IL. not sure. Kicked it up in a creek while bottle digging. Any thoughts or help would be great! Thanks