There isn't enough anatomical difference between a greyhound's left and right paws, front or back to warrant making individual boots for left and right, front or back. The only thing that really can vary is the size of foot, front to back. This is the reason we sell in pairs; to allow customers with a greyhound foot variance to choose the appropriate size. The exceptions to this are our slippers as they are mitten style and loose fitting.  Over time, the Summer boots can take on a molded "left and right" appearance, especially with repeated wetting and drying, and if yours do you can mark them as such somewhere inconspicuous. The L stamped on the bottom that can lead to confusion means Large (not Left) and is only present in size Large boots.