Thermarest - Boost 650 20F/-6C Morning Blue - Regular - Sleeping bag

Comfort isn’t one-size-fits-all, which is why the Boost 650 lets you customize its shape to achieve the perfect balance of space and warmth. Designed as a spacious semi-rectangular sleeping bag, it provides ample room for side sleeping, shifting positions, spreading out, and fully relaxing. Unlike a traditional mummy bag, the semi-rectangular shape offers significantly more internal space, allowing unrestricted movement for a comfortable night’s sleep. However, more space requires more body heat to stay warm, and that’s where WarmZip comes in. By zipping up the WarmZip center zipper, the Boost 650 transforms from a roomy semi-rectangular bag into a thermally efficient mummy bag. This feature pulls the 650-fill down closer to your body, minimizing excess space and enhancing warmth. WarmZip can increase the bag’s temperature rating by up to 10°F (6°C), ensuring extra comfort on colder nights. Additionally, the Boost 650 includes signature Therm-a-Rest features like a plush draft collar,