The vango ambience single sleeping bag is a rectangular sleeping bag that has an ingenious layering system so that you can easily convert this sleeping bag from a 3 season to a 2 season bag by unzipping one layer making this a fantastic and versatile sleeping bag the ambience single sleeping bag has a soft outer and a microfiber brushed polyester cosy snug and breathable lining to keep you comfortable making this versatile sleeping bag a great choice for camping caravanning and sleep overs