Big Agnes Farrington Primaloft Sleeping Bag

Sometimes having a bivvy sack in you ski-Touring day pack is enough, but when you get older you do need some extra piece of mind, Just in Case.
Weight of the insulation isn't given but it seems to be about 65GSM the same as a Nanopuff jacket. Can be compressed to a third the size of the little stuff sack so I can get a bit more gear into my pack and the total weight is so low I won't really notice it. That's the good part.
The bad news is that this is so skinny cut on the top half of the bag that anybody who wears a Mens large or bigger won't be able to close the zipper so I lose the benefit of a full length insulation layer and will need to carry something for my top half.
As an extra layer over a lightweight down bag in winter to get a temperature boost don't expect more than 5 degrees due to the fact that the insulation is stitched sewn though both shell layers so the benefit of windproofing on the exterior is lost. As a liner it might add at least ten degrees Celsius until the Primaloft Silver degrades but the Silver is a reasonable robust fibre. It's a cheap solution to a problem I just wish it was cut bigger around the chest and shoulders