The on-the-fly Boa® lacing system is an adjustable reel on the back of the shoe that controls ultra-thin strands of strategically placed, airplane-grade steel wires. A quick twist of the reel tightens the tiny strands and provides a unique fit that is unattainable in other comfort footwear. A simple pull on the reel releases the laces. It's the only therapeutic footwear offering the Boa® technology. Can't find the size you're looking for? Check out the Jacob.