Rip Curl Classic Surf Crossback Tri Bikini Top. We took some of our best selling swim pieces and made them even better by designing with the environment in mind. Our Eco Surf Collection pieces are made from regenerated nylon while still maintaining the great support and aesthetic we love about our Classic Surf styles. Our best-selling classic surf cross back tie bikini top, now made with regenerated nylon, offers the perfect coverage with cross back detailing. This fixed tri silhouette features adjustable coverage, removable padding and adjustable straps. This bikini top will be your go to year round.