ultracor Ultra Silk Knockout Legging in Black. - size XS (also in ) ultracor Ultra Silk Knockout Legging in Black. - size XS (also in ) Self: 84% nylon 16% lycraLining: 65% nylon 35% lycra. Elasticized waistband. Built-in shapeware. Metallic foil print star graphics. Laser-cut hem. Stretch fit. ULTR-WP11. 1USKL.