From Khyams popular VSS range, the Ultralight 1000 is a 2 to 3 season sleeping bag ideal for autumn winter backpacking especially where low weight is crucial. Double layer construction keeps the insulation evenly distributed, unlike down filled bags which are notorious for it clumping & producing cold spots. Thermlin filling used in the whole range dries more quickly than down but is just as warm. The Ultralight 1000 is wind resistant & highly breathable while remaining extremely compressable. Combined with Ultralight 600 or 800 for a go anywhere system for the cold nights, yet the two together still weigh less & take up less space than conventional sleeping bags & will be warmer weight for weight.