The Castelli Estremo 2 Shoe Covers are the nuclear option of the Italian manufacturer's anti element shoe cover line. The Italian estremo of their name translates to precipitation, wind, and temperatures as low as 28 degrees Fahrenheit. Extreme, indeed. The Estremo 2s are made from a windproof, water resistant, and insulating rubbery material that tops Castelli's offerings in all categories of winter protection except for water resistance. Even then, though, the only thing more waterproof is straight neoprene. The rear zips are waterproofed, and the rubberized sole is durable enough to stand up to the wet, cold abuse of the winter road. The Castelli Estremo 2 Shoe Covers are available in five sizes ranging from Small to XX Large in the colors Blackwhite and Blackyellow fluo. Please note that they are not compatible with mountain bike shoes.