This sleeping bag is very good performance at the height of 4000 meters. It is very light and comfortable. I loved that he had a double zipper. Very well packed and takes little space in your backpack. As for its water-resistant properties, I did not find specific deficiencies.
I took the Zissou sleeping bag to Mt. Whitney in March and I am in love with this product! It is extremely light but amazingly warm. The duck down worked awesome, I was in waste deep snow at some points but the Zissou never got wet. I will always buy Sierra Deign because of the Zissou!