Bison gws... the one i am looking for - Western Mountaineering Bison GWS -40 Sleeping Bag

Although I am not an expert in mountain trekking I have been enjoying mountain hiking and camping for years.
I believe when camping in the mountain top the sleeping bag is the most important item over tent, matress, etc. especially in winter season.

During winter the temperaure of most of Korean mountain like Seorak, Jirl and so on easily goes below -10 degree and often below -20 degree in Celsius. A couple of days ago (Dec. 30, 2017) I went to Halla Mt. which is the highest Mt. in south Korea and spent one night just about 150m below the summit. Thanks to the Western Mountaineering Bison GWS I had a safe and comfort sleep, and the windstopper fabrics of the Bison GWS protected me from the cold moisture of Halla Mt.

The price of the Bison GWS is not friendly, but If you are looking for a sleeping bag for an extreme winter condition I strongly recommend the Bison GWS.