The Perfect Fly "Crossover" Sling Pack is an alternate to a fly vest that can carry everything a large fly vest can carry and even more items such as a water bottle. It includes a special pocket to hold your landing net. The back panel has mesh lining to keep you cool. The Crossover's shoulder strap is very wide and padded so that it distributes the load equally and comfortably. The water bottle holder is at the bottom and out of the way of the fly fishing items.