Responsible Collection: Recycled/Repurposed Upper Material: full-grain leather Waterproofing: B-DRY membrane Insulation: 200g Primaloft BIO (100% recycled synthetic) Closure: slip-on, stretch gore panels Updated with larger stretch panels, a higher shaft, and greener insulation, the Big Sky II Mid Insulated B-DRY Boot is back for another round of winter hiking, sidewalk shoveling, and all-around adventure. Waterproof, full-grain leather with boosted protection from Oboz's B-DRY membrane keep our feet splash-free when we're storming through slushy puddles. Primaloft BIO insulation--made from 100% recycled and biodegradable materials--offers intense warmth, even in the coldest and wettest conditions. The Vibram sole, already thoroughly slip-proof, is improved with hike-ready lugs and Adaptive Cushioning Technology supporting each step.