It was the second general consumer sneaker to incorporate a computer,[1] after the Adidas 'Micropacer' in 1984.
[3] Requiring three years of development prior to release, the shoe adjusted itself after four strikes stride, using a motor in the middle of the sole.
The motor turned a screw, which in turn lengthened or shortens a cable, changing the compression characteristics of the heel pad.
The shoe was battery-powered, and lasted for approximately 100 hours of running.
There was an increased range of cushioning and a new motor with 153% more torque in the IL 1.1 upgrade.