Winter Wren False Bottom Sleeping Bag – Fetal Position

This is the Fetal Position version of the Winter Wren False Bottom Sleeping Bag. It has a huge differential cut to prevent the down from being compressed when the sleeper is curled up inside.

The Winter Wren Sleeping Bag is a full sleeping bag with a false bottom. This 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. 12″ of the total torso circumference is the false bottom. 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. It has horizontal baffles, a very large differential cut so you can’t compress the down fill in fetal position, a puffy draft collar, and super dense chambers 160% overstuffed with Hyperdry 900 fill power down. 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.

As mentioned, the fill on the underside of a sleeping bag doesn’t do much. It gets compressed under body weight rendering it mostly ineffective. I said “mostly” because it can do a little bit. Your body is not a totally flat surface and while your body points like hips, knees, and shoulders will completely compress the fill rendering it totally useless, the slightly suspended parts of your body will leave little gaps. Down on the underside can fill these and provide small amounts of added insulation. However, placing full height loft on the underside would be a huge waste since these gaps are usually only a half inch or so. For these reasons the Winter Wren is available with a lightly insulated false bottom with enough down to fill gaps and nothing more. This option adds approximately 1 ounce. The normal single layer fabric false bottom has had great feedback on warmth down to -10f so both options will be available.

See https://timmermade.com/sizing/sizing-sleep-systems/ for information on sizing.

This should be used with a Waterbear Balaclava or it can be used with other types of head insulation. https://timmermade.com/product-category/sleep-systems/balaclavas/

This can be paired with an overbag to manage moisture and boost it’s temperature rating. https://timmermade.com/product-category/sleep-systems/overbags/

See the “Technology” section on this site for information about this system’s features.