The multi award winning therm a rest neoair xtherm max mattress is the warmest mattress in the neoair range and with its small pack size and lightweight properties this mattress is ideal for alpinists ultralight backpackers and anyone wanting to get the best level of comfort for the smallest pack size and weight possible this full rectangle version of the xtherm mattress has extra width and length to offer added coverage and the most fantastic level of warmth and comfort the xtherm uses multiple