Sea to Summit official product photography (Reactor Lightweight Sleeping Bag Liner)
Sea to Summit
Thermolite Pro liner that the maker says can add up to 4 C / 7 F. Regular is $69.95.
Sea to Summit says the Reactor Lightweight can add up to 4 C / 7 F. Regular lists $69.95.
$64.95 to $74.95 Price checked Oct 13, 2026
seatosummit.com listed Short at $64.95, Regular at $69.95, and Long at $74.95 when checked. Source: Sea to Summit Reactor Lightweight Sleeping Bag Liner. Checked Oct 13, 2026. Confirm the price before you buy.
Sleep systems
A liner is the sleep piece that still fits a carry-on. Sea to Summit says the Reactor Lightweight uses Thermolite Pro and can add up to 4 C / 7 F when it is paired with a bag and pad.
The page lists Short $64.95, Regular $69.95, and Long $74.95. It is stretch knit, with arm openings, and the maker says it is machine washable.
Shortlist reason: a printed warmth claim and a size price, from the maker page.
| Added warmth | Up to 4 C / 7 F, per the maker seatosummit.com |
|---|---|
| Fabric | Thermolite Pro with hollow-core fibers seatosummit.com |
| Regular price | $69.95 seatosummit.com |
| Care | Machine washable seatosummit.com |
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