Let your feet out after a long day of trekking and indulge in the fresh mountain air wearing the Outdoor Research Tundra Slip-On Aerogel Booties. Weather-resistant polyester shell helps shed water and wind to protect your feet from the elements. PrimaLoft Aerogel inserts helps create a thermal barrier between your soles and the ground. VerticalX insulation offers an exception warmth-to-weight ratio while retaining heat even when wet. Collapsible heel can be worn up or down. Anti-slip sole provides reliable traction. Shell: 100 percent polyester; Lining: 100 percent tricot; Soles: 60 percent polyurethane, 40 percent polyester; Weight: 7.1 oz. Imported. Measurements: Weight: 2.8 oz Product measurements were taken using size M (Mens 6-9, Womens 7-9), width Medium. Please note that measurements may vary by size. Weight of footwear is based on a single item, not a pair.