There's a company that sells Mylar (Polyester) stencil material in various width/length rolls in 3 mil. with and without a removable adhesive, 5 and 6.5 mil clear that removes from its backing adhesive free. All are on a kraft backing and cut great. The 3 mil is called Poly-Cut, the 5 mil. is called Clear-Cut CCB5 and the 6.5 mil. is called Clear-Cut CCB7. They are available along with a wide range of other stencil materials from www.breninc.com.
Tom