#16 was popular because of it's durability. But thanks to VOC laws they stopped selling it. There have been rumors that it's still sold under the Meguiar's Marine line and outside of the USA. I have a couple of cans. It looks good, but extremely difficult to remove..but for that reason, it stays on the your car for a long time too. People pay $$ for it because it's not readily available in the USA.
