Therm-a-Rest Polar Ranger™ -20F/-30C Sleeping Bag

The Therm-a-Rest Polar Ranger -20F/-30C is an expedition-grade mummy bag rated for five-season use, built for winter ascents and polar-style trips where temperatures drop well below freezing. The fill is 800-fill-power goose down treated with Nikwax Hydrophobic Down, paired with a 20D recycled nylon ripstop shell and a ThermaCapture-coated liner that reflects body heat back toward the sleeper. At a manufacturer-rated comfort of -20°C and limit of -30°C, this is among the warmest bags in the lineup; at 1480 g (regular, up to 182 cm user height), the weight-to-warmth trade-off only makes sense when staying warm outranks staying light. A snorkel-style hood with magnetic closure, draft collar, draft tube, foot-box ventilation, and an internal pocket round out the expedition feature set, while SynergyLink connectors keep the bag anchored to a sleeping pad through the night. RDS certification confirms responsibly sourced down, and the shell is PFC-free. For standard three-season backpacking this bag is overbuilt and unnecessarily heavy — its case is winter mountaineering and expedition conditions where the low temperature rating actually gets used.