The Summit 250 Sleeping Bag is a 3-4 season bag, perfect for outdoor use in chilly weather. With increased insulation thanks to the mummy shape, youll be kept comfy and snug as you sleep. Season Rating - 3/4, perfect for use in cold to very cold temperatures Comfort Temperature - Ideal for temperatures -1C to 4C Extreme Temperature - Can be used for extreme temperature of -17C. This is a survival temperature only. The bag is not intended for regular use at this temperature. Fabric and Filling - 100% Polyester Ripstop shell with a soft polyester lining, hollowfibre insulation Zip - The zip system has a two-way closure system with storm flap and zip guard to prevent snagging. You can zip two of these bags together to create a double sleeping bag Shape - Mummy shaped for increased warmth Weight - 1.6kg Packed Diameter - 22cm X 40cm Personal Preference - Please remember that everyone feels the hot and cold differently. Always go with your personal preferenceRef: 023158.210627