Both pretty and functional. Need we say more?This Future Foundation Backless Strapless Bra offers stretch foam cups for shaping and light boning for a secure fit. Its low-set hook-and-eye closure and sweetheart neckline make it ideal for backless styles. Materials Front - 77% Nylon/ 23% Spandex; Back - 71% Nylon/ 29% Spandex; Cup Lining - 100% Polyester; Lining - 100% Nylon..