Optimized for minimal weight and maximum warmth, the Reactor Lightweight enhances sleep system performance with advanced Thermolite® Pro fabric, which uses infrared-absorbing ceramic pigments and hollow-core fibers to trap body heat. Adding up to 4°C|7°F of warmth with minimal bulk, it’s ideal for ultralight expeditions. Stretch-knit fabric and articulated arm openings ensure unrestricted mobility. Treated with HeiQ Fresh odor control, it’s quick-drying, machine washable, and helps prolong your sleeping bag’s lifespan by reducing wash frequency.

• Lightweight and insulative, Thermolite® Pro technology with hollow-core fibers and infrared-absorbing pigments enhances warmth with minimal pack size
  
• Freedom to Move – Stretch-knit and shaped arm openings allow unrestricted movement, providing natural comfort throughout your sleep
  
• Technical Shape and Hood – Ergonomic design with a fitted hood delivers optimal warmth and comfort without extra weight or bulk
  
• Fits any sleeping bag - Stretch fabric means the Reactor Liner fits any shape of sleeping bag
  
• Stay Fresh Longer – HeiQ Fresh odor control technology keeps the liner fresh after extended use
  
• Sleep System Integration – Snap connectors at the shoulders easily pair with Sea to Summit sleeping bags for quick, hassle-free entry and exit
  
• Easy to Keep Clean – Machine washable construction simplifies care and reduces wear on your sleeping bag over time
  
• Lower Impact Materials – Crafted with certified recycled fibers and bluesign APPROVED materials to minimize environmental impact
  
• 100% Post-Consumer Recycled Polyester
  
• Stuff Sack: 100% Polyester
  
• Dimensions: 70.1 x 31.5 in | 178 x 80 cm
  
• Packed Size: 3.9 x 7.1 x 3.9 in | 10 x 18 x 10 cm
  
• Weight: 8.3oz | 235g