Sawing logs and counting sheep are two of my favorite things, and they're both a lot easier at altitude with my phat ass parked on top of a beefy sleeping pad. The Big Agnes Insulated Air Core Mummy Pad can take the thunder, especially for you side sleepers out there like me who hate having your bony hips bottom out whilst tossing and turning.
I'm a big believer in the two-pad system for extreme cold: an inflatable parked on top of a closed cell foam pad will usually do the trick, and then you're also protected against pad failure. The Big Agnes Insulated Air Core series has long been a GearFlogger favorite, and this time up the mountain we packed the mummy version, size regular; it's also available in short and long versions. It performed flawlessly. Comfort was excellent, although larger folk with floppy limb syndrome might want to consider a wide version, unfortunately not available in mummy format.
The mummy is the lightest in this series at 21oz for 20x72in. Although I was a little concerned about having two extra corners, there were absolutely no problems aside from getting my lungs to work to inflate the big bastard. The extra air is needed to inflate the mummy to its 2.5 inches of glorious butt-absorbing goodness. Despite the beefiness the mummy compacts down to smaller than a 32oz Nalgene for excellent packability. Whichever Air Core you choose you can't go wrong.