The therm a rest prolite large self inflating mattress is the lightest most compact self inflating mattress from therm a rest designed for 3 season backpackers climbers and trekkers the tapered shape and use of die cut foam means that this self inflating mattress offers warmth and comfort while being highly compressible limiting bulk and weight the prolite large offers extra length and width for those who need a bit of extra room when camping the prolite features the new atmos foam which is excl