Opti-X Anti-slip Crew White Size:37 - 39 The backpack has an expand

The backpack has an expand function so it can expand from Daypack to Travel backpack with an extra 20% volume

Kanso symbol is intentionally designed to work as an integrated exo-skeleton to create stability for the upper

SA+ insert under heelbone to absorb negative forces

Compression stitching at ankle

Elastane for stretch

Opti-X Anti-slip Crew White Size:37 - 39 The backpack has an expandPerformance anti slip sock with compression technology stitching across the ankle for support. Featuring the latest technology in anti slip yarn and design for unrivalled performance and grip. One benefit is that the shoes does not need to be as tight to protect you from friction blizzards as the sock will provide anti slip features. Technical description features Ventilation channels V heel Compression stitching at ankle Thin pique knit upper and