With the rate that adidas is cranking out NMDs at the moment, you can bet that there are plenty of pairs produced that don't make it to retail.
Take this one for example, a heather grey creation that allows for a bright section on the back block attached to the Boost midsole. The owner of this sample says it's wool, but the material used on the upper looks rather like plain old mesh.
While this adidas NMD hasn't hit sneaker shelves yet, that doesn't preclude a future arrival. Readers can stay up on new info for the increasingly popular NMD silhouette here.
