As you will already knowthey are a much smaller vane, comes invarious sizes, eg. 1.5",1.8" etc. They're built FORD tuff, and does not fold with serious abuse.
Being smaller in size, less drag is introduced and when fletched with L/R helical the stability of the arrow improves.
For guys who aren't using adrop away rest--you can actually get quite a bit of helical without the vanes touching the launcher arm. As against the same amount of degree of helical on a longer vane-- can cause some problems with vane contact with the rest.