Sold in A5 or A4 sized pieces.
Stiff stuff is a great medium for making browband flags. You can draw on it in pencil or pen. Cut out with scissors, or a ruler and box cutter. I use it for making my browbands.
I use helmar fabric glue to attach ribbon to the stiff stuff.
You can use a double layer of stiff stuff or back with felt depending on the method you use to make your flags.