Three/Four Season Sleeping Bag.  Filled with 'Insufil', a 'siliconised hollowfiber. The synthetic fibers are structured to trap warm air between tiny cavities in the fibre. When unpacked the 'Hollowfibers' decompress and spring back to gain maximum re-loft. Inner lining is 'Supersoft', a silky smooth Nylon fabric. The latest yarn technology has been specially woven to produce a highly durable and comfortable lining. Outer fabric is lightweight nylon.