We designed the Synthetic Down Pac-Jacket for hunts that require a long trek to the place you want to hunt, often with your treestand and backpack in tow. You don't want to risk overheating by wearing too much clothing, but the last thing you need is more gear to carry. The Synthetic Down Pac-Jacket is highly compressible and packs into it's own chest pocket, making it easy to stuff in your backpack or clip to your belt. When you reach your hunting location and cool down from the walk, simply unpack the jacket and slip it on under your outer jacket to add lightweight, low-bulk insulation to any wardrobe. The jacket weighs just 13.2 ounces and measures 10" W x 8" H x 5" D when packed and can actually compress even smaller.