The Expander Liner series are the obvious choice for the price conscious traveller. They are made from a premium stretch-knit poly-cotton material which is super stretchy and even warmer than a standard cotton weave liner. The stretch properties allow the Expander to move with you as you sleep, vastly increasing comfort and minimising tangles. The anti-microbial treatment keeps bacteria at bay as well as prolonging the life of your liner and sleeping bag. The anti-microbial treatment won t wash out of the liner, and does not use nano-sized particles. The treatment is approved for use by the EPA (USA) and is used in many hospitals.
The Expander Liner series are the obvious choice for the price conscious traveller. They are made from a premium stretch-knit poly-cotton material which is super stretchy and even warmer than a standard cotton weave liner. The stretch properties allow the Expander to move with you as you sleep, vastly increasing comfort and minimising tangles. The anti-microbial treatment keeps bacteria at bay as well as prolonging the life of your liner and sleeping bag. The anti-microbial treatment won t wash out of the liner, and does not use nano-sized particles. The treatment is approved for use by the EPA (USA) and is used in many hospitals.
in 7 offers
last seen 27 Apr 2026
The lowest price we last saw for Sea to Summit Expander Liner - Double Navy was $35.00 at Snowys Outdoors, compared across 6 retailers (last seen 27 Apr 2026). Prices may have changed since.
The all-time low we recorded was $35.00 on 5 June 2024.
Prices last updated 27 Apr 2026.
Sea to Summit Expander Liner - Double Navy
The Expander Liner series are the obvious choice for the price conscious traveller. They are made from a premium stretch-knit poly-cotton material which is super stretchy and even warmer than a standard cotton weave liner. The stretch properties allow the Expander to move with you as you sleep, vastly increasing comfort and minimising tangles. The anti-microbial treatment keeps bacteria at bay as well as prolonging the life of your liner and sleeping bag. The anti-microbial treatment won t wash out of the liner, and does not use nano-sized particles. The treatment is approved for use by the EPA (USA) and is used in many hospitals.
The Expander Liner series are the obvious choice for the price conscious traveller. They are made from a premium stretch-knit poly-cotton material which is super stretchy and even warmer than a standard cotton weave liner. The stretch properties allow the Expander to move with you as you sleep, vastly increasing comfort and minimising tangles. The anti-microbial treatment keeps bacteria at bay as well as prolonging the life of your liner and sleeping bag. The anti-microbial treatment won t wash out of the liner, and does not use nano-sized particles. The treatment is approved for use by the EPA (USA) and is used in many hospitals.
Last updated at 27/04/2026 19:14:31
Expander Liner - Double
Free 60-day returns
Sea To Summit Expander Double Liner - Navy
Sea To Summit Expander Liner - Double
Delivery $9.80
Sea To Summit Expander Double Sleep Liner
Delivery between 1–12 May $10
Sea to Summit Expander Liner Navy / Double - Valhalla Tactical & Outdoor
Delivery $15
Sea to Summit Expander Liner Sleeping Bag Liner DOUBLE / Navy | Boss Outdoor
originally posted on seatosummitusa.com
I used this for a 2-night hut-to-hut ski adventure in Oregon. This liner was lightweight, compact, and snuggly soft. It felt great, launders well and is a super economical option for keeping a layer between me and the sleeping bag.
originally posted on seatosummitusa.com
This product is essential and provides guard between my hide and airplane seat or helps keep cleaner down sleeping bag. Can see in dark (bright green). Keeps biting cooties off me! ( I also pack lots of wet wipes in plastic bag--total nerd, but being sick overseas horrible! prevention EVERYTHING).Can relax and sleep. Cozy too. Pull over head and snore away. Your mates will be envious. I use it alone; inside sleeping bag, hostels, air planes, trains, subways, bunks, hotels, busses, sleeping in double bed with others; ALL sketchy or even "luxury" sleeping options.... you don't know who was there before! (total nerd; I bring my own STS towels and pillow covers). Liner washes well; could use alone when hot for sleeping bag, and rolls up into small nothing. Shake out; ... MoreThis product is essential and provides guard between my hide and airplane seat or helps keep cleaner down sleeping bag. Can see in dark (bright green). Keeps biting cooties off me! ( I also pack lots of wet wipes in plastic bag--total nerd, but being sick overseas horrible! prevention EVERYTHING).Can relax and sleep. Cozy too. Pull over head and snore away. Your mates will be envious. I use it alone; inside sleeping bag, hostels, air planes, trains, subways, bunks, hotels, busses, sleeping in double bed with others; ALL sketchy or even "luxury" sleeping options.... you don't know who was there before! (total nerd; I bring my own STS towels and pillow covers). Liner washes well; could use alone when hot for sleeping bag, and rolls up into small nothing. Shake out; roll up. Stuff into pack or bag Secure with rubber band; wrap in plastic; or small water-proof stuff sack. It goes with you! Mine traveled all over the world before global pandemics.Would not think of not having it now. Insect Shield (r) another level of protection . Not just for camping either. General sleeping hygiene product. Sawyer makes a spray product for reapplication of insect shield at REI. Absolutely essential product. Pack mine with nice-smelling dryer sheet. Total nerd.
originally posted on seatosummitusa.com
I got this for my son for Boyscouts instead of sending him with a much bulkier and heavier twin sheet set because we do so many hiking and camping trips where he carries his own weight. He used it on a 4-day trip where we hammock camped. To save weight, he packed only this liner, a small lightweight travel blanket that folds into about an 8” square pillow, and a sleeping pad for his sleeping system along with his hammock. The temperature dropped from about 80 degrees F to between 50-60 at night and he stayed perfectly comfortable. He liked the liner so much he used it in his bed at home and also took it on a week-long camping trip with the Boyscouts where they slept on cots. Both of us are very satisfied with the purchase. I’m so glad he’s not having to lug around a ... MoreI got this for my son for Boyscouts instead of sending him with a much bulkier and heavier twin sheet set because we do so many hiking and camping trips where he carries his own weight. He used it on a 4-day trip where we hammock camped. To save weight, he packed only this liner, a small lightweight travel blanket that folds into about an 8” square pillow, and a sleeping pad for his sleeping system along with his hammock. The temperature dropped from about 80 degrees F to between 50-60 at night and he stayed perfectly comfortable. He liked the liner so much he used it in his bed at home and also took it on a week-long camping trip with the Boyscouts where they slept on cots. Both of us are very satisfied with the purchase. I’m so glad he’s not having to lug around a ton of weight and also so he has a layer to keep his top-layer sleeping gear clean. The ability to layer is what you need for colder trips and this is a great addition to his gear!
| Length | 73 inches |
| Shape | Rectangular |
| Outer Material | Cotton |
| Season | 3 Seasons |
| Seal material type | Cotton |
Expander Liner - Double
Free 60-day returns
Sea To Summit Expander Double Liner - Navy
Sea To Summit Expander Liner - Double
Delivery $9.80
Sea To Summit Expander Double Sleep Liner
Delivery between 1–12 May $10
Sea to Summit Expander Liner Navy / Double - Valhalla Tactical & Outdoor
Delivery $15
I used this for a 2-night hut-to-hut ski adventure in Oregon. This liner was lightweight, compact, and snuggly soft. It felt great, launders well and is a super economical option for keeping a layer between me and the sleeping bag.
This product is essential and provides guard between my hide and airplane seat or helps keep cleaner down sleeping bag. Can see in dark (bright green). Keeps biting cooties off me! ( I also pack lots of wet wipes in plastic bag--total nerd, but being sick overseas horrible! prevention EVERYTHING).Can relax and sleep. Cozy too. Pull over head and snore away. Your mates will be envious. I use it alone; inside sleeping bag, hostels, air planes, trains, subways, bunks, hotels, busses, sleeping in double bed with others; ALL sketchy or even "luxury" sleeping options.... you don't know who was there before! (total nerd; I bring my own STS towels and pillow covers). Liner washes well; could use alone when hot for sleeping bag, and rolls up into small nothing. Shake out; ... MoreThis product is essential and provides guard between my hide and airplane seat or helps keep cleaner down sleeping bag. Can see in dark (bright green). Keeps biting cooties off me! ( I also pack lots of wet wipes in plastic bag--total nerd, but being sick overseas horrible! prevention EVERYTHING).Can relax and sleep. Cozy too. Pull over head and snore away. Your mates will be envious. I use it alone; inside sleeping bag, hostels, air planes, trains, subways, bunks, hotels, busses, sleeping in double bed with others; ALL sketchy or even "luxury" sleeping options.... you don't know who was there before! (total nerd; I bring my own STS towels and pillow covers). Liner washes well; could use alone when hot for sleeping bag, and rolls up into small nothing. Shake out; roll up. Stuff into pack or bag Secure with rubber band; wrap in plastic; or small water-proof stuff sack. It goes with you! Mine traveled all over the world before global pandemics.Would not think of not having it now. Insect Shield (r) another level of protection . Not just for camping either. General sleeping hygiene product. Sawyer makes a spray product for reapplication of insect shield at REI. Absolutely essential product. Pack mine with nice-smelling dryer sheet. Total nerd.
I got this for my son for Boyscouts instead of sending him with a much bulkier and heavier twin sheet set because we do so many hiking and camping trips where he carries his own weight. He used it on a 4-day trip where we hammock camped. To save weight, he packed only this liner, a small lightweight travel blanket that folds into about an 8” square pillow, and a sleeping pad for his sleeping system along with his hammock. The temperature dropped from about 80 degrees F to between 50-60 at night and he stayed perfectly comfortable. He liked the liner so much he used it in his bed at home and also took it on a week-long camping trip with the Boyscouts where they slept on cots. Both of us are very satisfied with the purchase. I’m so glad he’s not having to lug around a ... MoreI got this for my son for Boyscouts instead of sending him with a much bulkier and heavier twin sheet set because we do so many hiking and camping trips where he carries his own weight. He used it on a 4-day trip where we hammock camped. To save weight, he packed only this liner, a small lightweight travel blanket that folds into about an 8” square pillow, and a sleeping pad for his sleeping system along with his hammock. The temperature dropped from about 80 degrees F to between 50-60 at night and he stayed perfectly comfortable. He liked the liner so much he used it in his bed at home and also took it on a week-long camping trip with the Boyscouts where they slept on cots. Both of us are very satisfied with the purchase. I’m so glad he’s not having to lug around a ton of weight and also so he has a layer to keep his top-layer sleeping gear clean. The ability to layer is what you need for colder trips and this is a great addition to his gear!
I loved this. It's lightweight and super soft and cozy for two people, or extra luxurious for one! It's now also my go to summer sleeping bag in warm climates (Utah, Texas, even New York etc.). Whish the bag it packs in was a bittt bigger and easy to pack in, so I'd give that a 3 star, but the product itself is definitely 5.
Recently got a double sleeping bag and thought a liner would be a great addition! Fabric is so soft and comfortable and on some of the warmer eves in the desert it's all you need. Such a treat to be able to snuggle with my person, and have enough space to move around too!
The material of the expander travel liner is soft and comfortable, like a nice sheet. It is so stretchy, however, that it gets twisted around me when I sleep. It almost looks like it has been sewn a little crooked, but I think that is just the material. My biggest complaint is that the extra material for the pillow is not big enough to cover a standard size pillow. I don’t know if that is normal for sleeping bag liners but that doesn’t make sense to me, since it makes it non-functional as a cover for a pillow.
I have all of these sea to summit liners and while they all have there purpose the expander is the best. It's an all arounder that lets your feet move freely. Now this the expander for two people. Pretty good but you might be better off just getting two single expanders.
Product is 'as advertised' warm and cosy and very stretchy.Even though the product is super stretchy, it's kind of like playing tug of war with an elesatic band. The fabric stretches but you can then feel the resistance pulling back agaisnt each other.My wife and I found we both got tangled up and we ended up removing it after one night sleep and slept much better in just our sleeping bag.I'm sure it would be great for one person, but in a queen bag it made things worse for us and not better.Product was of good quality though and definitely added warmth. Too much so for us in our 0 degree bag
I was hoping that this liner would give us some warmness in the spring camp near Whistler in BC. It is very compact and looks warmer in the photo but unfortunately, the actual product material looks very thin and I will have to return it. I like the idea of a double liner but we might have to get an individual reactor liner instead.
super stretchy and super soft, it felt great to sleep on - we actually used it as a protective slip for our camping mattress. The weight is significant, though, if you are backpacking, compared to the silk liner from Sea to summit we already own. Wished Sea to summit made a synthetic liner that was lighter, as we don't need it for warmth, just to protect our sleeping backs and/or mattress.
| Length | 73 inches |
| Shape | Rectangular |
| Outer Material | Cotton |
| Season | 3 Seasons |
| Seal material type | Cotton |
