

🔥 Sleep warmer, move freer, and stay fresher—your ultimate camping upgrade!
The Sea to Summit Reactor Insulated Sleeping Bag Liner uses advanced Thermolite Pro technology with hollow-core fibers and infrared ceramic pigments to reflect body heat, enhancing warmth without bulk. Featuring an adjustable drawcord footbox for personalized comfort and HeiQ Fresh odor control for lasting freshness, this stretchy mummy-shaped liner fits seamlessly with most sleeping bags. Lightweight and durable, it’s designed for 3-season use and backed by a lifetime guarantee, making it a must-have for millennial adventurers seeking warmth, hygiene, and freedom on the trail.












| ASIN | B0CT6B4WGH |
| Age Range (Description) | Adult |
| Best Sellers Rank | #11,533 in Sports & Outdoors ( See Top 100 in Sports & Outdoors ) #5 in Camping Sleeping Bag Liners |
| Brand | Sea to Summit |
| Brand Name | Sea to Summit |
| Closure Type | Drawstring |
| Color | Sulphur Yellow |
| Country of Origin | China |
| Customer Reviews | 4.7 4.7 out of 5 stars (247) |
| Date First Available | January 24, 2024 |
| Fabric Type | thermolite |
| Fill Material | Thermolite |
| Fill Material Type | Thermolite |
| Global Trade Identification Number | 09327868158430 |
| Item Dimensions LxWxH | 78 x 31 x 1 inches |
| Item Package Dimensions L x W x H | 7.52 x 4.69 x 3.78 inches |
| Item Weight | 0.67 Pounds |
| Manufacturer | Sea to Summit |
| Material | thermolite |
| Maximum Height Recommendation | 7 Feet |
| Occupancy | 1 |
| Outer Material | thermolite |
| Package Weight | 0.31 Kilograms |
| Part Number | ASL031061-190906 |
| Seasons | 3 Seasons |
| Shape | Mummy |
| Size | Regular Standard (85 x 31.5) |
| Style | Regular Standard (85 X 31.5) |
| Suggested Users | unisex |
| Temperature Rating | 31 to 45 degrees Celsius |
| Thermal Resistance | 7.78 Watts per Meter per Degree Celsius |
J**K
Warm and comfortable.
Kept me pretty warm with my 32F down sleeping bag in 25F weather. My feet got a little cold but wasn’t bad enough to keep me up all night.
C**R
Great liner for summer months
i’m not keeping this because I need something a little warmer. I’m getting ready to start the Appalachian Trail and I just don’t think this is warm enough for me looking for a warmer insulated liner for my sleeping bag. If I wouldn’t be hiking in the cold, I probably would’ve kept it.
W**N
It worked for me!
First night was in the 20’s f and worked great with my sleep system. I woke up to a small amount of snow and was warm without feeling drafts in my hammock. I use this every time in my sleep system
C**6
Works great
Works great. My bag went from adequate to comfortable, with minimal weight added to my pack.
B**.
Sleeping bag liner.
This bag liner is nice and warm. Drawstring bottom is great for sitting around the fire and keeping your legs warm. The snaps and hood helps keeps wrapped around you while you roll around at night. Was out for a cold evening and usually sleep in my puffy. Ended up taking it off in the middle of the night cause the liner was keeping me extra warm.
J**.
Very warm, easy to get in and out of
I used this for several nights in 30 degree temps as a liner in my hammock, combined with a 20 degree top and under quilt. With just the 20 degree quilts I would have been way too cold with the wind chill. However this liner provided more than enough extra insulation for the conditions. Also, the easy close foot box made it very convenient to get in and out of, especially with the added difficulty of hammock camping.
J**K
Versatile and effective both as a warmth-increasing line and as a standalone bag
I bought this to store in my camper as a 'just in case' item or spare, and have been very pleased with it. It definitely adds warmth to a main sleeping bag without making one feel clammy inside, and it works nicely as a light bag on warmer nights. The open footbox adds further versatility (you can close it with a drawstring for maximum warmth) too. If you're through-hiking the AT, it's too bulky and heavy to justify taking along, but if you do RV camping or are going out for one or two nights and expect variable weather, this is a very worthwhile addition to your kit.
W**R
Sleeping bag liner.
Very happy with this quality liner. Definitely worth buying
A**A
I used this to increase warmth in my 3 season nemo sleeping bag, it’s lightweight, thin fleece which yiu don’t expect to make much difference. However it’s amazing, excellent, warmed up straight away, it’s soft , cosy against your skin and makes the sleeping inside my sleeping bag a totally cosy , lovely experience. It’s pricey, but worth it.
M**N
Ich habe den Reactor gekauft, um meinen Schlafsack in gelegentlich kälteren Nächten damit zu ergänzen. Das kommt mal vor, wenn man zum Beispiel aus dem Süden über die Alpen nach Hause unterwegs ist und das Lager irgendwo in den Bergen aufstellen muss. Mein Sommer-Schlafsack hält mich warm bis etwas 12 Grad. Darunter fühle ich die Kälte deutlich. Zusammen mit dem Reactor aber habe ich bereits 8 Grad kalte Nächte konfortabel durchgeschlafen. Das Ding ist auch allein in warmen Nächten als Schlafsack recht nützlich, wenn man in den weiter südlich wärmeren Klimen unterwegs ist, zum Beispiel in Griechenland oder Süd-Spanien.
Y**N
No lo he utilizado todavía pero cumple con la descripción
C**S
SeaToSummitの新型ライナー3つのうち、一番温かいモデル。 最初混乱したが、保温性はリアクターライナーが最低、リアクターエクストリームライナーが中間、リアクターフリースライナー(この製品)が最高ということになっている。最上位モデルにエクストリームと名付けるわけではないらしい。3つのうちで、この製品だけがThermolite®Proを使っていないので、商品説明にもこの製品だけ「身体が発する赤外線を吸収/反射する」という文言がない。ライナーで体の熱を反射しちゃったらシュラフに熱が伝わらないから結局寒いんじゃないの?という疑問は、とりあえずこの製品には関係ない。 シュラフの中でジップとコードを完全に締めると非常に温かい。何なら暑い。ところが肩や腕がライナーから出るようにすると途端に寒く感じる。試しにシュラフなしでライナーだけにくるまってみると外気に触れている部分が妙に寒く、一方でマットに触れている側は妙に暑い。 思うに、「内側(普通は人間の体)の熱をよく受け取る、自身の蓄熱性もそれなりに高い、外側(普通はシュラフ)にも自身の熱をよく渡す」ということではなかろうか。要するに単なるフリースだ。 正直、温度調整がピーキーでかなり難しいと感じた。 構造はジップやボタンなど結構複雑で、暗い中手探りで開け閉めしたり位置を整えるのが割とストレス。いっそ単なる巾着構造にしてくれと叫びたくなる。シュラフの中で微妙な寒暖に合わせて開放具合を調節・・・とかやってられない。 肌触りは悪くはないが、特に良いとも思わない。 身長170cmちょっとなので長さ198cmのコンパクトで十分かと思ったが少し足らなかった(なんでだ)。 コンパクトでも本体のみで403gあり、それほど軽いわけではない。ほとんど圧縮できないので量的にもかさばる。 手持ち寝具への温かさの追加を求めるなら、シュラフカバーか追加キルトが先で、それでも足りないと想定される時に初めてこのライナーの携行が選択肢に挙がると思う。 夏のシュラフ替わりという選択肢も提示されているが、わざわざこの重くてかさばって温度調整の難しい製品である必要はないと思う。
F**T
Matériaux très doux, très agréables pour dormir, surtout si l'on utilise un duvet technique qui n’est pas très confortable habituellement. Une sensation de chaleur est aussi observée
Trustpilot
1 week ago
4 days ago