Cumulus Teneqa 850

At the top of the Cumulus winter range sits the Teneqa 850, an expedition mummy bag with 850 g of Polish goose down at 850 fill power (96/4 ratio). Comfort -15 °C, limit -23 °C, extreme -46 °C — figures from Cumulus's own testing that put this into serious cold-weather territory: high-altitude expeditions, polar-adjacent trips, or deep winter bivouacs where an ordinary winter bag would not suffice. Total weight is 1310 g. Despite carrying more down than any other bag here, its warmth-to-weight figures are the most efficient of the Cumulus sleep systems reviewed, helped by vertical baffle chambers, an anatomical footbox, and an insulated draft collar and tube along the full-length two-way zipper, mounted left rather than the usual right side. Down is RDS-certified, two bags can be zipped together into a double. The Pertex Quantum 29 g/m² shell and internal pocket round out an expedition-grade package for users up to 190 cm. Not a bag for general backpacking — it earns its 1.3 kg only on trips where extreme cold is an actual, not hypothetical, risk.