Do any Sea to Summit sleeping bag / travel liners have side zippers? Do any Sea to Summit sleeping bag / travel liners have side zippers?

Do any Sea to Summit sleeping bag / travel liners have side zippers?

No. A full-length zip would add bulk and weight and reduce packability. 

Other closures, including hook-and-loop, were tested but didn't suit the liner fabrics and were hard to use in the dark.

Since 2024, the Reactor, Reactor Fleece and Breeze Mummy liners have shoulder openings for your arms and a drawcord footbox opening for your feet. 

To get up at night, slide your feet and arms out and "wear" the liner.

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