The Therm-A-Rest ProLite 8482 is the lightest most compact self-inflating mattress from Therm-A-Rest designed for 3 season backpackers climbers and trekkers This is the REGULAR size version and thanks to the tapered shape and use of die-cut foam core this self inflating mattress offers excellent warmth and comfort while being highly compressible limiting bulk and weight The ProLite mat self inflates with just a twist of the valve the foam core expands and then you just top it off with just a few breaths to make it as firm as you like for a comfortable and well supported nights sleep