Icebreaker Siren Bra

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Made with a soft, durable merino blend to regulate body temperatures in all weather conditions, the Icebreaker Siren bra is lightly supportive and endlessly comfortable for easy everyday layering.

  • Features

    • Ultralight 150 g core-spun fabric is made with merino fibers wrapped around nylon cores for underwear that is durable and soft next to your skin
    • Merino is an annually renewable fiber that naturally resists odors, keeps you cool when it's hot and warm when it's not, and lets your skin breathe for comfort all day
    • This ZQ merino wool has been granted equivalency to the RWS (Responsible Wool Standard)
    • Space to insert bra cups
    • Modern fit features thin, adjustable straps and no side seams
    • Inspired by nature, Icebreaker harnesses the performance qualities of natural fibers to offer an alternative to clothing based on petrochemical synthetics


    View all Icebreaker Women's Sports Bras
  • Technical Specs

    Best Use



    83% merino wool/12% nylon/5% elastane

    Bra Support

    Low Impact

    Support Style


    Strap Type

    Tank Top

    Adjustable Straps





    Wool certified to the Responsible Wool Standard (RWS)

  • Size Chart

    XS S M L XL
    Chest or Bust 30 - 32 32 - 34 34 - 37 37 - 40 40 - 42

    Sizing Notes

    Measurements are stated in inches unless otherwise indicated.

  • Reviews
    260 reviews with an average rating of 4.4 out of 5 stars

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