Sea to Summit Reactor

Gear Review: Sleeping bag liner

Company: Sea to Summit

Product: THERMOLITE® Reactor™ liner

A piece of gear you may not know that you want need.  The Reactor is essentially a sleeping bag liner, but it’s more than just a sleeping bag liner, it’s a money saver, a time saver, a gear saver, and if you’re as dramatic as me, you would call it a life saver!

A quick side note on sleeping bags, just because a sleeping bag is rated to zero, ten, twenty, or thirty degrees, it doesn’t mean you will be comfortable at those temps.  What that rating amounts to is the notion that you’ll survive in those temperatures.  What this means is that if you have a sleeping bag rated to twenty degrees, and temps fall below twenty-five, that may make for an uncomfortable evening.  You’ll be alive, but uncomfortable.

I have a pretty good sleeping bag rated for pretty low temps, but survival and comfort are two different things!  All this ignores that fact that a sleeping bag rated for such low temps becomes useless when the temps reach scalding heights in the summer months.  It also ignores the wear, tear, and overall nastiness of months long expeditions which lack access to showers, baths, and other hygienic amenities.  The classic sleeping bag is an absolute life safer, but it’s not the ideal multi-tool that some hope for or claim it to be.

The Reactor fixes all that!  Depending on which Reactor model you look at, these little beasts can add up to thirty-two degrees of warmth to your sleeping bag.  I settled on the classic Reactor which adds up to fourteen degrees of warmth.  Gone are the days where I shiver every time temps drop into the twenties!  This thing weighs ½ a pound and is smaller than ½ a loaf of bread (when stowed).  I’m pretty sure it’s made of whatever magical threads were used to make the elven cloak of invisibility from Load of the Rings.  The Sea to Summit website says it’s made of hollow core fibers which trap heat and offer extraordinary insulating properties, but that still sounds like elven magic to me!

Okay so the magic threads offer fourteen to thirty-two degrees of warmth to your bag, what else can they do?  Well in the summer when evening temps maintain in the mid-nineties, no one wants to be inside a sleeping bag dripping sweat from parts they didn’t realize could drip.  But no one wants to miss out on the snuggle feel of being wrapped up either.  The Reactor is the perfect solution.  The Reactor is so soft that you’ll feel as is mama and papa elf are holding you in the palm of their snuggly magic bliss (I don’t really know elf lore, but I imagine elves offer snuggly magic bliss).  In other words, The Reactor allows you to drop the sleeping bag, and keep the snugs!

So, The Reactor keeps you warm on the cold days and comfy on the hot nights, it’s as soft as an edelweiss, and the kicker is that you will never have to go through the pains of washing or dry-cleaning your sleeping bag ever again!  The Reactor is machine safe using standard laundry detergent!  This means the next time you get off a LOOOOOOOOONG trip covered in dirt and sweat, smelling like rotten pork doused in vinegar, you just toss The Reactor into that wash machine and call it a day!

A clean, warm, cool, hygienic addition to your sleeping system.  A piece of gear you didn’t know you needed, but you do!  The Reactor!

Recommendation: All campers, all levels.

Specs: 8.7oz, +14 Degrees, Liner 6’10” x 36” (Stuff Sack 5.7” x 4”)

MSPR: $62.95.

Website: af97a286-99d4-4136-946b-3138b3c3b94d._cr00600180_pt0_sx600__ 


10 Replies to “Sea to Summit Reactor”

  1. This is great a review! I learned the hard way about the temperate rating on a bag, doesn’t necessarily mean you’ll be comfortable.
    I love Sea to Summit, so I’m definitely putting this on my wish list. Thanks for the info 🙂

    Liked by 1 person

  2. Curious as to how well it stays in the bag. I had a sleeping bag liner once (albeit a very cheap one) and I could never get it into the bag right and then every time I turned it wrapped around me.
    Just wondering if I should try a better one

    Liked by 1 person

    1. That is a very good question…I didn’t mention it here because that problem never presented itself. When I was ready to sleep I just popped into the liner and then into my sleeping bag. I was able to keep my arms between the liner and my bag, and the back always seemed to stay in place. I’ll have to pay more attention next time, but like I said this problem has yet to present itself, which I think is a good sign.


  3. I love my Reactors. There are 3 versions. The classic, the thermolite (red) and the fleece (grey). I have the red for general use and staying in backpackers where you don’t trust the beds. And the grey one for any winter and snow camping. It’s basically a thin polar fleece sleeping bag. And it is amazing. I highly recommend them over silk liners in cold conditions.

    Liked by 1 person

  4. Thank you for sharing this review. I could purchase it in Japan, so I bought for my hiking. The Reactor is really warm and, nice texture. Thank you so much!

    Liked by 1 person

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