Wren false bottom sleeping bag
The Wren sleeping bag is a full sleeping bag that wraps all the way around the sleeper, just without the insulation in the bottom where it is compressed and has limited effectiveness in a traditional bag. This design pushes weight savings well below traditional bags and even below quilts, but performs totally draft free like a full sleeping bag. Venting is accomplished with the top drawcord and/or with the bottom drawcord at the footbox. The Wren has horizontal baffles, a full differential cut so you can't compress the down fill, and has a drawstring footbox that allows you to vent. It also is fully wearable and can be used as a jacket or for warmth around camp just like the quilt version, however the false bottom version limits the use of your arms a bit more when used as a garment. It is important with any sleep system that it is paired with a sleeping pad rated to similar temperatures. It is especially important with quilts and false bottom bags and it should be noted that pads that utilize empty spaces are generally not suitable for these types of sleep systems.
This should be used with a Waterbear hood or can be used with other types of head insulation.
http://www.timmermade.com/store/p18/Climashield_Waterbear_hood.html
http://www.timmermade.com/store/p72/Down_Waterbear_hood.html
This can be paired with a Merganser overbag that clips together with it
http://www.timmermade.com/synthetic-overbag-for-moisture-management.html
All sleep systems are 20% overstuffed.
Read up on the design features:
http://www.timmermade.com/false-bottom-sleep-system.html
http://www.timmermade.com/camping-quilts.html
http://www.timmermade.com/differential-cut.html
http://www.timmermade.com/horizontal-baffles.html
http://www.timmermade.com/non-integrated-hood-sleep-systems.html
http://www.timmermade.com/overstuff.html
Approximate weights can be found here. Scroll down to the model, then to the size/temp rating to find weight.