Which sleeping bag liner should I choose?

For simplicity, let's divide the lineup into travel and backpacking liners.

The Rectangular Silk Blend, Breeze and Comfort Blend liners are aimed primarily at travelers - they offer a clean, hygienic sleep environment wherever you find yourself at the end of the day. They also work for car-camping.

Mummy-shaped Coolmax Breeze liners are designed for use inside sleeping bags in warm and humid weather. The Coolmax fabric does not cool you down, but it spreads perspiration effectively so it can dissipate effectively. This process (known as moisture management) prevents you from feeling clammy on warmer nights. When the weather is really warm, you may just sleep in a Breeze instead of a sleeping bag. Breeze liners are great for anyone who prefers a stretch knit fabric (like a quality T-Shirt) instead of a woven fabric. Because of this comfort factor, even mummy-shaped Breeze liners are therefore popular with travelers as well as backpackers.

Consumers based in the USA can also purchase Insect Shield-treated versions of the Breeze which offer great protection against certain insects.

Thermolite Reactor liners are made for increasing the warmth of your sleeping bag in colder temperatures. Hollow-core fibers trap insulating air, a factor enhanced by the 'three dimensional' knitted structure of the liners and the infrared-absorbing ceramic pigments in the yarns.

Reactors can be used as standalone sleeping bag substitutes in warm weather (just be aware that they are not windproof - moving air will take away the warmth you have generated).

2024 Breeze and Reactor Liners also feature openings in the shoulder and in the footbox. This increases ventilation, but also makes the liner incredibly practical:

- You can sit up in your tent, stretch your arms through the shoulder openings of the liner (and your Free Flow sleeping bag zippers) and read or enjoy a cup of coffee.

- You can pull the liner up and 'wear' it outside of your sleeping bag - hitch it up if you need a nighttime bathroom break.

If you are conscious of the weight of your gear, the clear choice will be the Silk Blend liner. As mentioned above it is available in a Rectangular shape which is ideal for travel - but in mummy form, it is the go-to for gram-counting backpackers.

A liner is far easier to wash than a sleeping bag. Wash your liner after every trip, or at every zero day on a thru-hike. Your sleeping bag will remain free of oils and salts from your skin plus fine-grain sand from your feet and lower legs - it will last much longer.

Lastly, a word about fit: If you have ever tried a liner and found it to be constrictive, or if you have a sleeping bag with a non-traditional shape, we would direct you to the Breeze or Reactor series – their knitted fabric is really stretchy.