Best for the thing almost nobody owns
Sea to Summit Thermolite Reactor Liner
Adds warmth and keeps body oils out of a bag's insulation. Experienced campers know and still skip it.
The clearest example of an under-bought item: it is cheap, it protects an expensive bag, and almost nobody buys one. <strong>Check first:</strong> whether they already have one. See <a href="/trail/best-sleeping-bags">sleeping bags</a>.
Specs
- Thermolite fabric liner
- Manufacturer-stated warmth gain of several degrees
- Packs very small
- Machine washable
Good for
- Extends an expensive sleeping bag's life by years
- Washable, where a down bag is a careful once-in-a-while job
- Also usable alone as a hot-weather sheet or in hostels
Bad at
- Manufacturer warmth claims in this category are generous
- Can twist and bunch while you sleep
- They may already have one
