I have spent many a night testing and trying to find a fault with this rather unique sleeping bag design.

While the mobility aspect may seem funny at first, this is only due to the fact that the concept is a foreign one. Once you put the Sierra Designs Mobile Mummy 800 to the test its easy to be won over and realize that this could be the new direction for all sleeping bag designs.

With a comfort rating of only 4°C and a Limit rating (more for us guys) of -2°C it was easy for me to find the Mobile Mummy 800 warmer that comparable sleeping bags. My nights out in the field were between 0°C and 5°C and were no problem for the Mobile Mummy. No cold spots of dead air because I was using the entire bag to sleep in and it moved as I did. It's also a simple matter to get your arms out, unzipping the centre zipper to create room for your knees to move or to pull your legs out of the bag completely without ever having to actually leave the sleeping bag. This opens up a world of possibilities for staying warm yet being functional.

Read the complete review of the Sierra Designs Mobile Mummy 800 on our sleeping bag review page here or give the video below a watch:

Arms out to read or fiddle with your headlamp.

Legs out to stretch or go water a tree.