Manufacturers of insulating clothing are increasingly opting for wool fillings instead of down or synthetic fibers. The small, young sleeping bag brand Grüezi Bag takes up this idea and launches the Biopod Zero (1040 g, 199 euros), a hybrid of synthetic fibers and wool. "The unique concept works: Thanks to the wool layer, the Biopod offers the well-tempered sleeping climate typical of natural materials - without being as sensitive to moisture as a down sleeping bag," explains online editorexcited after several nights. The synthetic layer, in turn, improves the thermal performance because it insulates better than wool at the same weight. As a result, the Biopod can be used up to four degrees (outdoor temperature range*: 12/4 °C). »I also like the zipper that runs over the sleeping bag at ankle height. So I can stick my feet out,« Bücheler praises another special feature of the Biopod, whose wool comes from the Alps . Pack size: only six liters.