The Kaos shoes are built upon the Millenium 4 Outsole, which is a nylon matrix infused with carbon fiber. The mixed compound is resistant to heat and humidity, ensuring that your soles will outlast replacement heel pads and buckles, which are available separately. The uppers are a breathable synthetic leather lined with a microfiber to keep your feet cool and dry. Unlike leather, the synthetic will not stretch and provides consistent support for your feet. To secure the shoes, Sidi placed its ratcheting buckle at the ankle sewn to a wide band to reduce pressure. At the forefoot are two Techo 3 buckles. These feature a twist and tighten mechanism that allows micro adjustments. Both are easy to adjust in the saddle.