Allbirds Men's Tree Loungers - Black Size 11 Great Preowned condition Keep things light and breezy with our slip-on sneakers made with lightweight eucalyptus tree fiber that gives you maximum comfort in a minimalist design.Best For: Walking, warmer weather, everyday wearThermoregulating Material: Lightweight, breathable eucalyptus fiber provides next-level comfortVersatile Design: Wear-with-everything classic style, great for travel