FREYA SWIM. In The Mix Underwire 50's Halter Tankini is a great basic black Tankini. It features underwire cups with a plunging centre front finished off with a cute frill down the neckline. Ties around the neck and sits comfortably on the hips. Co-ordinate with the following briefs, Hipster, Latino or Skirted, each providing a certain amount of desired coverage.