From the Hobb's web site:
Thermore® Ultra Thin Batting-
This unique and patented product was developed as a thin, drapable, migration free polyester batt. Thermore® is now considered the premium polyester batting for apparel, miniatures and other projects requiring a thin, non-bearding batting. Thermore® can be quilted up to 6-8” apart and is wonderful to quilt by hand or machine.