stylish all round and superbly protected from the elements. . durable, water-repellent technology and 10k breathability are just some of the benefits of the oakley sierra insulated jacket.oakley fn dryâ„¢ fabric, 80g insulation and o protect dwr provide protection from the elements, and the adjustable hood, elastic cuffs and snow gaiter keep you comfortable for all your snow activities.stylish for apres-ski, the sierra jacket features a slightly looser-fitting performance fit and contrasting colour details.