Pellon 860F Ultra-Weft Fusible Interfacing 20″ x 10 yards Bolt. Color: White. Fiber Content: 85% Rayon/15% Polyester. Application Method: Fusible. Ultra-Weft is a woven, fusible, weft insertion interfacing for traditional soft tailoring and designer drape in lightweight jackets and coats. It was developed for fabrics such as lightweight wool, cashmere, camel hair, and crepe.