Roxy Little Girls'  Sundown Tw Tri One Piece Stripe Swimsuit 80% Nylon/20% Spandex Imported Hand Wash Less than a one-piece but more than a bikini, this halter monokini features cut-out sides for a fresh and modern fit. Made from an extra strong and incredibly resilient nylon-spandex blend, this super swim fabric is smooth to the touch and will protect her skin from rashing.