Sidi Avast Rain Shoes The reinforced heel keeps the foot in a optimal position and avoids the shoe being deformed by extreme performance or prolonged pressure. Replaceable Heel Pad For walkability, Sidi cycling shoes include a replaceable polyurethane heel pad. Millenium 3 Sole The Millennium 3 sole is a sleek, modern redesign of the Millennium 2 sole. By fortifying the sole with carbon fiber, Sidi designers have created a sole that improves on the technical characteristics of the previous nylon sole. It is constructed out of injected carbon fiber in a nylon matrix. The infusion of carbon fiber gives the sole more rigidity than the previous sole. The Millennium 3 is more durable and less susceptible to changes in stiffness resulting from prolonged usage and changes in The Millennium 3 features a replaceable non-slip polyurethane heel pad. The heel pad is held in place by a screw. The Millennium 3 is compatible with the best road pedals on the market. To facilitate cleat replacement, the Millennium 4 sole features a 10 mm horizontal and vertical cleat alignment scale molded into the sole as well as the Look Memory Eyelet.