Pellon 926 Sew-In Extra-Firm Stabilizer 20″ x 10 yards Bolt. Color: White. Fiber Content: 100% Polyester. Application Method: Sew-In. Extra-Firm Stabilizer is a sew-in heavyweight stabilizer. It is a firm yet flexible interfacing that is perfect for shaping into purses, bowls, and other 3D craft projects. It is easy to cut, mark, and sew and is sewing machine safe.