Review: Sea to Summit Coolmax Adaptor Traveller Liner with Insect Shield

Review: Sea to Summit Coolmax Adaptor Traveller Liner with Insect Shield

Whether I’m walking the Camino de Santiago or hiking the Via Francigena, one of my essential pieces fo backpacking gear is the Sea to Summit Coolmax Adaptor Traveller Liner with Insect Shield. Designed as a lightweight, packable addition to your sleeping kit, this breathable barrier is essential to keeping you and your gear from coming into contact with bed bugs and other unsanitary conditions, especially in high-volume sleeping quarters such as hostels and albergues where the daily turn of guests and packs create an ideal environment for bedbugs.



The Sea to Summit Traveller Adapter Bed Liner with Insect Shield is made from Coolmax (a moisture-wicking polyester) to create a thin, breathable layer that feels like your favorite t-shirt. This is not a liner that is going to keep you warm; on the contrary, this is a layer for staying cool in warm environments. The material would be easily mistaken for cotton or bamboo with its excellent feel and softness but works to keep you cool in any warm or humid environment.

Available in a mummy-bag shape or as a rectangular sleeping liner, the fabric is pre-treated with permethrin at the thread/yarn stage of production to help repel mosquitoes, ticks, bedbugs, midges and fleas. This production stage treatment nets a 182-percent reduction in the user’s exposure to chemicals while ensuring the long-term protection from bed bugs for up to 70 washings. (Note: More information on the permethrin treatment process and safe usage are available online from InsectShield.)

The bed liner packs neatly into its own ultrasil stuff sack – taking up less space in your backpack than a solo cup – and weighs just 11 ounces.


Sea to Summit Coolmax Adaptor Traveller Liner with Insect Shield

The Adaptor COOLMAX Liner with Insect Shield is an excellent versatile choice for your buggiest adventures. It will adapt to varied temperatures and humidity and is ideal for use on its own in warm climates, or as a liner in your regular sleeping bag. The COOLMAX fabric is super soft and luxuriously comfortable, kind of like your favorite tee shirt and with its moisture-wicking properties, it will help to provide a dreamy sleep wherever you are.

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In my experience, the Sea to Summit Traveller Adapter Bed Liner with Insect Shield is an unbeatable layer of protection from bedbugs and other unhygienic sleeping situations in hostels or other public sleeping quarters. I’ve even used this in hotels where I was unsure of the cleanliness, as there’s no reason to take chances with bedbugs or fleas while backpacking.

If you’re not familiar with permethrin, rest assured that the Insect Shield treatment is a well-studied and extremely effective repellent from bed bugs, ticks, fleas and other crawlies. Recommended for use directly on clothes or skin, it is the number one preventative against a number of insect-borne illnesses and diseases. The Insect Shield pre-treatment in this liner is completely odorless and leaves no residue.

Simply lay the liner out onto your hostel bed and climb in. Whether you are a side sleeper or not, there is enough room within the liner to keep your pillow and any blanket layer you may choose separated from the mattress and other layers.  This liner will definitely keep you free from bed bugs during the Camino de Santiago; however, this is not a liner to use as a full replacement for a sleeping bag in outdoor conditions. This lightweight layer functions more like a bug-free set of travel sheets.



Sea to Summit Coolmax Adaptor Traveller Liner with Insect Shield

Features:5 out of 5 stars (5.0 / 5)
Comfort:5 out of 5 stars (5.0 / 5)
Durability:5 out of 5 stars (5.0 / 5)
Packability:5 out of 5 stars (5.0 / 5)
Adjustability:5 out of 5 stars (5.0 / 5)
Value:4 out of 5 stars (4.0 / 5)
Average:4.8 out of 5 stars (4.8 / 5)


  • COOLMAX® polyester provides moisture-wicking, quick-drying comfort and offers the lightweight, softness of cotton
  • Use the liner as a part of your sleep system or by itself as a warm-weather ultralight sleeping bag
  • Traveller shape is 89 in. long and 36 in. wide, and it includes a pillow pocket for your pillow
  • Liner helps keep the inside of your sleeping bag clean, saving it from the wear and tear of washings
  • Contrasting color along the top edge makes it easy to find the opening
  • Comes with a lightweight Ultra-Sil™ stuff sack


As of 2019, the Sea to Summit Traveller Adapter Bed Liner with Insect Shield retails for $70. While not inexpensive, this bed liner serves as a sanitary layer of protection from bedbugs, fleas and ticks. This is an essential part of my sleep system and a critical part of my recommended packing list for any trekking trips that may involve sleeping in a hostel or albergue.



NOTE: I purchased the Sea to Summit Coolmax Traveler Liner with Insect Shield on my own and did not receive any incentive for providing this review. The views expressed regarding this product are mine alone based on my own experiences. If you purchase an item linked from this site, I may receive a small commission at no cost to you.