The Siren is Icebreaker's take on a casual activity bra made from blended merino wool, making it perfect for activities like yoga class and everyday wear. It’s made from merino with Corespun fabric technology, which uses nylon fibres wrapped in merino wool for added strength that retains its next-to-skin softness. The Siren bra has a sleek design with no-side-seams, making it incredibly comfortable and easy to layer. Its lightweight, elastic, and easily adjustable shoulder straps have a barely-there feel.