Do you hear that? It's the silence in your tent when your bag doesn't have a zipper. No more zzzzzzip sounds when you want to get in and out of your bag quietly. The Thunderhead SL bag features cozy cocoon style construction with an easy, weight-saving clip and loop system in place of the traditional zipper. With an integrated half pad sleeve on the bottom, a vaulted foot box with ample wiggle room, and vertically structured side walls that trap heat closer to your body, this 650 fill power DownTek(TM) bag is the perfect all-in-one sleeping bag for backpacking or any backcountry outing.Features:Cocoon style construction features easy to use clip and loop system eliminating the need for a zipperOversized interior anti draft collar wraps around the entire body providing a 3D barrier against cold spots Vertically structured side walls integrating diagonal baffles trap heat closer to the bodyVaulted foot box creates more wiggle room for your feetIntegrated half pad sleeve with unique design keeps you securely attached to the pad from the hips up while allowing freedom of movement for your legs, more like a traditional mummy bagSuperlight shell fabric with high tear strength DownTek(TM) water repellent down repels water while maintaining insulating valueLow profile cordlock lets you un-cinch the hood with one handInterior fabric loops for sleeping bag linersExterior loops for hang drying or storageMesh storage sack & nylon stuff sackVideo -Big Agnes Brooklyn 0