Extreme insulation for committed winter bivouacking
Designed for harsh environments, the Aegismax D5 extreme cold sleeping bag is a true thermal barrier for expeditions in freezing conditions. Achieving a comfort temperature of -17°C requires a significant amount of down fill, skillfully distributed within a snug mummy cut. This winter sleeping bag drastically limits body heat loss, ensuring a secure night's sleep when the cold settles in for the long haul.
Thermal barrier and insulating finishes
The efficiency of this model relies on crucial details: an ultra-enveloping multi-chamber hood, an imposing thermal collar, and an anti-cold tube positioned along the zipper. The 650 cuin RDS-certified down retains its structural integrity even after several days of compression. The DWR nylon outer membrane blocks frost and humidity, ensuring absolute reliability of the down in hostile environments.
Full-baffle structure against cold spots
The internal construction relies on continuous transverse baffles that partition the RDS-certified duck down across the entire width of the bag. At a comfort rating of -17°C, this uniform distribution limits the risk of localized cold spots on this extreme cold weather down, in addition to the multi-chamber hood and draft collar already featured on this model.
Technical components: YKK zip and Duraflex buckles
The zipper uses a YKK 5 Nylon zip and the adjustment buckles are Duraflex, two components renowned in outdoor equipment for their durability over time. The snag-free PAIHO velcro protects the outer fabric from gradual damage during repeated handling of this winter sleeping bag.
To face even more extreme temperatures (-23°C) without weighing down your bag or pulk, the transition to the fill power of the premium goose down in the Aegismax G5 model will be the appropriate technical solution.
Doubt about which bag is right for you?
The field guide helps you choose based on skill level, temperature, needs, and weight. Support answers specific questions.
Find my bag Contact supportFrequently Asked Questions
The Aegismax D5 has a comfort temperature of -17°C and a lower limit temperature of -25°C, measured to the EN 13537 standard. These values apply under standard conditions: sleeper in thermal base layers, on an insulated sleeping mat. It is designed for Mountaineering, expedition use (4 seasons / Extreme cold).
The Aegismax D5 is filled with 650 fill power, RDS certified. The Aegismax D5 weighs 1768 g, which places it in the standard category.
Yes, provided they are used within their real temperature range. A cold-weather bag is designed to keep the sleeper warm below -10°C, but its effectiveness also depends on the insulated sleeping mat (R-value 4 minimum), the clothes worn at night and ambient humidity. The bag alone does not guarantee comfort: it is the complete sleep system that counts.
Several factors determine real thermal comfort: using a sleeping mat with a suitable R-value (R4 minimum for extreme cold), wearing thermal base layers and dry socks, eating enough before sleeping to fuel body-heat production, and making sure the bag is completely dry. A damp bag loses a significant part of its insulating properties, especially down.
The lower limit temperature is the lowest temperature at which a reference man can maintain his body heat curled up, according to EN 13537 / ISO 23537-1. It usually sits a few degrees below the comfort temperature, and the gap varies between models: check the figure on each product page. Below this threshold, comfort is no longer assured — the comfort temperature remains the main selection criterion.