The jack wolfskin 4 in 1 blanket 5 is an incredibly versatile 3 season rectangular sleeping bag that can be used in four different ways thanks to the way the sleeping bag has a detachable liner and the way the bag itself can be unzipped fully to offer you many different combinations of use the blanket 5 can be used as a traditional season 3 rectangular sleeping bag with liner it has a single layer of microguard synthetic insulation with cold sensitive areas for additional insulation and a soft f