For all my single color vinyl graphics that I make I use Oracal 651. It's a better quality vinyl than 641. Most graphics/sign companies that use Oracal products use 651 as their standard. Additionally, 651 is just a bit thinner and more flexible than 641 which makes it easier to cover with poly. 651 also lasts a few years longer than 641. Oracal lists 651 as an intermediate film and 641 as an economy film.