Mountain equipment classic 500 sleeping bag left zip spacious and comfortable a perfect all round bag for use during the spring summer and autumn in temperate climates features helium tm 40 outer shell is lightweight and breathable 433g of 90 10 pure duck down with a minimum fill power of 700 mountain fit is both spacious and thermally efficient slanted box wall baffles throughout mid level side seams 5 baffle anatomically shaped hood 2 baffle anatomically shaped and offset foot