The air chambers are filled with 60 gsm Texpedloft microfibre insulation, so you not only get a comfortable, ground levelling mat, it keeps you warm down to minus 4 degrees Celsius. This means you can afford to take a lighter sleeping bag, keeping your pack weight to a minimum. The lightweight outer is waterproof, air tight & abrasion resistant, has a soft next-to-the-skin feel & is also slip resistant. A proprietary Exped lamination is completely airtight & impervious to degradation. Exped are so sure of their manufacturing quality that they give this mat a 2 year warranty on materials & workmanship. Inflation is via separate inflation & deflation flat valve technology & can be done by mouth in about 1.5 minutes, but we recommend either a Schnozzel or Schnozzel Pump Bag for hassle free instant inflation without introducing moisture to the filling. A sleeping bag is only as good as the mat it lies on, once you get in your sleeping bag you compress all the insulation that’s underneath you, rendering it practically useless. Therefore it is essential to have a good insulating mat to protect you from the cold ground.