Exosphere 3.5If youre looking for comfort, durability and ease of use, our self inflating Exosphere 3. 5 sleep mat is ideal. Its X Core foam filling is supportive and insulating, ensuring you get a rejuvenating night ready for tomorrows adventures. This foam uses X core technology which is a 3 dimensional weight relieved structure. This saves weight and reduces pack size, but also traps air to boost warmth and contributes towards the mats R value of 3. 4, while