All birds Grey Mizzles water resistant made with merino wool.EVERYDAY SNEAKER: Lightweight, breathable, warm in the cold and cool in the heat, the versatile Wool Runners men’s casual shoe is a wildly comfortable everyday walking sneaker offering a sporty-casual style with premium durability and a lightweight airy feel.SIZING TIP: If you are in between sizes or have wide feet, we recommend you size up. The Wool Runners are available in whole sizes only.HIGH-QUALITY WOOL: The upper is made of super fine and cozy, natural ZQ Merino wool. This natural fiber is versatile; it is warm and luxurious for autumn and winter wear and lightweight/moisture regulating for spring and summer wear, its softness provides the ideal itch-free comfort and enhanced breathability for daily wear.COMFORTABLE MIDSOLE: Delightfully bouncy midsole made from sugarcane provides cushioned, springy support for wear-all-day comfort.MACHINE WASHABLE: Allbirds shoes are machine washable! Our all-natural materials will not lose any performance or shape after being washed, simply place in a delicates bag and wash on cold gentle cycle; air dry for 24 hours.