3 pack of one color or 4 pack containing one of each - These are the glitter Art Edge sheets used to make the outlines for the stained glass style bead mosaics.  You can cut them down into strips as thin as needed for your project and they look like beads with thier glitter and sparkle.
These sheets are 2mm thick and self adhesive.  Be careful of cheaper ones they tend to be thinner and dont stick as well.
Buy a 3 pack of a single color or a multi-pack with all four colors
Available in Gold, White, Black or Silver.
Check out the Bead Mosaic YouTube videos showing you how to cut them.