When it comes to staying warm on the mountain, layering is key. The L.L.Bean Down Sweater 3 in 1 Jacket combines a lightweight down jacket and sturdy waterproof shell that can be zipped, allowing it to be worn in three configurations. The 3 in one is essentially two jackets that combine to become one. The … More L.L.Bean Down Sweater 3-in-1 Jacket Review