Internally, warmth is provided through a high quality MICROGUARD insulation, a soft and robust 2-component synethetic fill designed with its high insulating warmth properties. Additional comfort on the Smoozip +3 is gained through thermozone technology, providing extra insulation and a fleece lining on areas that have been specified as prone to losing body heat, retaining this heat to attain a comfortable nights sleep. With an ergonomic, S shaped zip, Jack Wolfskin have designed the Smoozip -5 for simplistic opening, allowing the bag to be opened or closed with one swift movement, preventing the possibility of snagging or awkwardly unzipping. When bedding down for the night, the hood can be used as a flat pillow and when colder, cinched around the head to keep heat close.