Birki Air 2.0 by Birkenstock Sold out online! Worn once to work and not for me Color: Matcha Size: 40 These run BIG - I am a size 9 and usually wear 40 in Arizona's and other Birkenstock styles. Even with the strap down I had about a half inch or so of extra space. The toe box is also wide so these kept slipping off my feet. A great shoe for standing for long periods but not for a lot of walking.