This bag is wide, warm, and packed with features. With a 3-dimensional full down collar, a full-length YKK zipper, and 5 inches of loft, the Alpinlite has quickly become one of our most popular models. Our award winning Ultralite has been a favorite among lightweight backpackers for more than a decade. The Alpinlite is just a wide version of that great bag. There are many 20 down mummy bags on the market, but none have the width, warmth, or loft of this bag.