The lacing system is comprised of a series of pulleys powered by a rechargeable battery. Just step into the shoes and sensors register your weight and foot position, and then adjust the laces accordingly. You can adjust the tightness of the laces by pushing a plus or minus button the side of the shoe.
Because the shoes operate on battery power, they do require charging a couple of times a month which may be an issue for potential buyers. In the future Nike is suggesting the shoe will be able to make these micro adjustments on its own as well as gathering biometric data that feed the companies line of wearables.