from Xero shoes site: Lightweight protection that feels just right. The Z-Trail EV features an updated 11 mm FeelLite™ sole with a middle layer of TrailFoam™ and an updated dual chevron lug pattern that offers the best combination of comfort, protection, and trail-ready traction while still allowing you to bend, move, flex, and feel the terrain beneath your feet. At just 4.3 oz each for a women’s 7, the Z-Trail EV remains just as lightweight and packable as the original best-selling Z-Trail.