The Sea to Summit Reactor Extreme Thermolite® Liner is your go-to solution for cold-weather adventures. As the warmest liner in Sea to Summit’s lineup, it increases your sleeping bag's warmth by up to 25°F (15°C), thanks to the advanced THERMOLITE® fabric. Its hollow-core fibers mimic polar bear fur, trapping insulating air and providing exceptional warmth without added bulk.

The technical mummy shape with a drawstring hood ensures a snug fit, while the stretchy, 110g/m² Thermolite® fabric delivers unparalleled comfort. This versatile liner is perfect for extending your sleeping bag’s range in colder climates or serving as a lightweight stand-alone sleeping bag in milder weather. Plus, it helps keep your sleeping bag clean, making it a must-have for backpackers and campers.

Packing down to just 6.5 x 4.5 inches in its included Ultra-Sil™ stuff sack, this liner is lightweight at 14 oz (399 g) and easy to care for—machine washable with no special detergents required.

Key Features:

• Maximum Warmth: Adds up to 25°F (15°C) to your sleeping bag’s temperature rating.
• Thermolite® Fabric: Hollow-core fibers trap insulating air for superior warmth and comfort.
• Mummy Shape: Features a drawstring hood for a snug fit and maximum efficiency.
• Compact & Lightweight: Packs into its own Ultra-Sil™ stuff sack for easy transport.
• Versatile Use: Works as a sleeping bag liner in cold climates or a stand-alone bag in warmer weather.
• Easy Maintenance: Machine washable for convenience.

Specifications:

• Best Use: Backpacking & Camping
• Weight: 14 oz (399 g)
• Length: 6 ft 10 in (210 cm)
• Packed Size: 6.5 x 4.5 in (17 x 11.5 cm)
• Material: Thermolite® 110g/m² fabric