Therm-a-Rest Questar™ 0F/-18C Sleeping Bag

The Questar 0F/-18C is a winter mummy bag from Therm-a-Rest's Questar line, EN ISO 23537-tested to a -10°C comfort rating and -18°C limit, with an extreme rating of -40°C. The fill is 650-fill-power goose down treated with Nikwax Hydrophobic Down and RDS-certified; at 820 g of fill, total bag weight comes to 1210 g (Regular, up to 183 cm), a reasonable ratio for a four-season/winter bag, though not exceptionally light compared with higher fill-power down. The shell is 20D ripstop polyester with DWR treatment, lined with 20D polyester taffeta. A two-way, full-length zipper allows venting even in cold conditions, while a draft collar and draft tube limit heat loss, and an internal pocket plus SynergyLink pad loops round out the feature set. Both a stuff sack and a storage sack are included. The bag is made in China and carries a one-year warranty. It's a solid pick for winter treks and high-altitude conditions where the -10°C comfort rating will actually be used.