This is self adhesive backed vinyl that is typically used for lettering on signs. It's also used to make decals or stickers that people put on their vehicles or windows.
Forgive my stupidity, but I want to use these a certain way. By self-adhesive, do you mean the vinyl sticks to surfaces like windows and cars by itself, or is there something like a peel-off back sheet that exposes a glue adhesive?
Your questions are more than welcome. It has a thick paper backing that needs to be peeled off to expose the adhesive back and will stick to many smooth surfaces. Once applied, this material is waterproof and weather proof for 6 - 8 years.