Allbirds Tree Breezers Flats Machine Washable Grey Size 7.5. Crafted with silky-smooth eucalyptus tree fiber and a fitted collar, these machine washable ballet flat never misses a beat. The lightweight, breathable eucalyptus fiber provides next-level comfort. • Ribbed collar provides a perfectly secure fit • Renewable Materials • Machine Washable • Flexibility Conforms To Your Movements • Removable Insoles Not only are they comfortable, they are also functional and easily transition from day to night. Good preloved condition, with some signs of wear.