Allbirds Women's Tree Runner, NWOB/New Without Box, Color is Calm Teal (Blue) w/ Blizzard Sole. - Breathable: Tree Knit is naturally airy and pleasantly cool. - Lightweight: Flexible, functional and made to move. - Responsibly Sourced: Made w/ Tencel Lyocell blend upper and castor bean oil-based insole foam. - Supportive: Surgarcane-based Sweet Foam midsole is both sturdy and super soft. - Washing machine approved.