Thermarest centari winter synthetic sleeping bag green nebula this synthetic winter sleeping bag is now even warmer the centari sleeping bag is the cozy cocoon you want for frigid winter nights weve upped the bags warmth without adding bulk thanks to our advanced thermacaputure tm seams and the water resistant eraloft tm synthetic insulation is light compressible and provides a high degree of warmth in wet conditions commonly found in winter camping our synergylink tm connectors al