450-fill-power duck down insulation compresses easily for packingPolyester shells feature a Durable Water Repellent to fend off moisture and light rainSoft polyester fleece linings are heaven on bare feet; elasticized instep straps keep booties secureEVA midsoles help REI Down booties provide cushioning underfoot; polyester soles sport polyurethane beads for enhanced tractionREI Down Bootie sizing: Small fits men's shoe sizes 7 - 8 Medium fits men's shoe sizes 8.5 - 9.5 Large fits men's shoe sizes 10 - 11 X Large fits men's shoe sizes 11.5 - 13Imported. Item 855499