Best Cold Weather Sleeping Bags of 2025 Outdoor Life Thermarest Questar 0F 18C Sleeping Bag Thermarest The Sleeping Bag Store Thermarest Questar 0: Versatile and lightweight sleeping bag for cold. Thermarest Questar 0F 18C Sleeping Bag When winter camping, ice fishing trips, or late season backcountry routes push temperatures well below freezing, the Therm a Rest Questar 0F 18C delivers the warmth and comfort features needed for a genuine night's rest in serious cold. The fill is 650 fill Nikwax Hydrophobic Down, RDS certified and PFC free, absorbing 90% less water and drying three times faster than untreated down. Box baffled construction uses mesh walls to maximise loft and eliminate cold spots throughout the bag, while Zoned Insulation concentrates fill over your core and shoulders where heat retention is critical and reduces it where your sleeping pad handles insulation from below. The W. A. R. M. fit was refined in Therm a Rest's onsite cold chamber to provide room for natural sleep positions without opening up thermal gaps on cold nights. The Toe asis foot pocket concentrates down insulation in the footbox to warm cold feet quickly after a hard day in winter conditions. SynergyLink Connectors keep the bag anchored to your sleeping pad for a sleep system that stays aligned through the night, and they detach cleanly when you'd rather use the bag independently. Quilt and blanket loops allow layering with additional Therm a Rest pieces for the coldest nights. Available in three sizes fitting both men and women. Temperature rating: 0F 18C Fill: 650 fill Nikwax Hydrophobic Down (RDS certified, PFC free) Absorbs 90% less water, dries 3x faster than untreated down Construction: Box baffled with mesh walls Fit: W. A. R. M. (With Additional Room for Multiple positions) Zoned Insulation for targeted warmth efficiency SynergyLink Connectors for pad integration (removable) Toe asis down lined foot warmer pocket Quilt and blanket loops for system layering Features: draft collar, zipper draft tube, snag free zipper, cinchable hood, external zip pocket Includes compression sack and storage sack