Radical 12ZWinter sleeping bag (–14°C)

Radical 12Z is the sleeping bag you take when you know the night ahead will be under a wall of ice, in a snow cave, or on the approach to K2.

It’s filled with 880 grams of premium Polish white goose down from Kołuda (900 CUIN), enclosed in Z-shaped baffles that prevent thermal bridges from forming. Combined with a carefully engineered thermal structure, it maximizes the down’s insulating potential – and keeps the cold out.

We used a mummy-shaped cut, narrowing toward the bottom to reduce the amount of air that needs to be heated and to help the interior warm up faster. At the same time, there’s still enough room to sleep in a down jacket or extra layers.

The sleeping bag wraps around the body evenly, protecting the most sensitive areas – neck, shoulders, chest, and head. For extra insulation, we added a down-filled draft collar that fits closely around the neck and shoulders, blocking cold air from entering. The hood can be adjusted easily and precisely, even with gloves on – thanks to an intuitive drawcord system. Inside, there’s a thin IRL (Infrared Reflective Layer) that reflects body heat back toward the center of the sleeping bag.

The outer shell is made of GELANOTS® Ultra Light Ripstop Shell – resistant to snow, moisture, and abrasion, yet breathable. Thanks to the HMS (Humidity Management System) and waterproof panels in the head and foot zones, the sleeping bag handles moisture more effectively – helping the down stay lofty and maintain its insulating properties longer.

The YKK zipper runs smoothly even in thick gloves, while the insulating draft tubes sewn along its length keep warmth inside. On the outside, you’ll find drying loops, and the set includes two storage bags – a compression sack for transport and a loose mesh bag for storage between expeditions.

We’ve tested it in the Himalayas. We’ve proven it during the descent from K2.
It’s ready for everything that lies ahead.