Spanx Spanx's 'Undie-tectable' thongs have elastic-free edges, making them invisible underneath your clothing. Cut from stretch-jersey and lace, they have a wide bonded waistband that's designed to smooth and sculpt your stomach. Wear yours with fitted dresses or slim pants. Wear it with: Calvin Klein Underwear Bra, Alighieri Necklace. - Black and beige stretch-jersey and lace - Lined at the base - 78% nylon, 22% elastane; trim: 80% nylon, 20% elastane - Machine wash - Designer color: Very Black/ Soft Nude - Imported