These forms are made a synthetic material infused with fiberglass to allow full pinning for lifetime use. The forms are covered with an Irish linen with the high thread count. They are also sewn with straight princess seams front and back as well as under bust seams, french dart seams and side seams. Forms come completely lined with black bias tape for the pants and for waist area as well as for your arm length. They come with collapsible retractable shoulder to allow easy garment put on. The forms are based for American standard sizing with complete accuracy.