A universal thermal insert for blanket sleeping bags that increases thermal comfort. It is made of highly breathable 100% PES fleece material that is soft and smooth to the touch. Also suitable as a separate blanket. Other advantages are the small volume, low weight and transport packaging. A universal thermal insert for blanket sleeping bags that increases thermal comfort. It is made of highly breathable 100% PES fleece material that is soft and smooth to the touch. Also suitable as a separate blanket. Other advantages are the small volume, low weight and transport packaging.