Rooster Hot Socks - a revolution in warmth - a 0.5mm titanium layer that is both comfortable and warm. Wear them under your normal sailing boots for extra warmth - remember layers are better than thickness! Titanium neoprene acts in a similar way to a survival blanket, the titanium impregnated reflective layer is sandwiched between the neoprene and the interior nylon lining, this lining reflects radiated heat back to the body.We recommend hand washing in warm soapy water and allowing to air dry. FEATURES Thin neoprene socks with 0.5mm Titanium impregnated reflective layer Sailing Survival Blanket – Provide additional warmth by reflecting heat back to the body Layer up with PolyPro Socks Sizing UK 3.5 4 4.5 5 5.5 6 6.5 7 7.5 Europe 36.5 37 38 38.5 39 40 40.5 41 42 USA 4.5 5 5.5 6 6.5 6.5 7 7.5 8 Rooster 2XS 2XS XS XS S S S M M   UK 8 8.5 9 9.5 10 10.5 11 11.5 12 Europe 42.5 43 44 44.5 45 45.5 46 46.5 47 USA 8.5 9 9.5 10 10.5 11 11.5 12 12.5 Rooster ML ML ML L L L XL XL 2XL Nb. If you have wide feet or a high instep we recommend you opt for the next size up.