The THERMOLITE Reactor liner is our top selling and lightest thermal sleeping bag liner. It's an excellent cold weather option for those who need additional warmth. The hollow core fibers trap heat and offer extraordinary insulating properties. This is a super stretchy, soft, and comfortable choice with a mummy shape, foot box and a drawcord hood. Compact and lighter weight than fleece, this is a best seller for good reason.

Features:

• Traps insulating air to increase warmth of a sleeping bag by up to 14°F /8°C
• Stretchy, Thermolite fabric is incredibly comfortable.
• Lighter weight and more packable than fleece.
• Technical mummy-shape with drawstring hood.
• Easy care – machine wash with no special soap is needed. Avoid fabric softeners and dryer sheets.
• Keeps sleeping bag clean.
• Packs into its own Ultra-Sil stuff sack.