Whatever the journey, Sidi Aertis is there to make it easier and better. The comfort of a premium suede construction meets Firmor Closure technology to offer great lateral support. The nylon sole with replaceable rubber insert allows for maximum grip in any situation and increased walking comfort. -Designed for maximum lateral support the Firmor Closure contours the foot with a solid hold, and allows infinite size adjustment for the ideal individual fit -Sidi's Tecno-3 System dials in fit along the entire length of the shoe, adapting the upper to the shape of the foot for a customized fit -The closure uses a new proprietary Sidi Wire monofilament that is completely non-binding for intuitive and effortless on-the-fly adjustments -Like most Sidi small parts, the Tecno-3 System is serviceable and replaceable -The Sidi MTB SR17 sole represents the ultimate result in terms of stiffness for pedaling and flexibility for walking -The toe inserts are easily replaceable and offer the possibility to mount spikes for particularly muddy rides