--- title: "Sea To Summit Reactor Midweight Liner" name: "Sea To Summit Reactor Midweight Liner" brand: "Sea To Summit" description: "The Sea to Summit Reactor Midweight liner boosts your sleeping bag's thermal comfort by up to 6°C (11°F)." handle: "sea-to-summit-reactor-midweight-liner" sku: "053303" ean: "9327868169818" gtin: "9327868169818" canonical_url: "https://gramino.com/p/sea-to-summit-reactor-midweight-liner" html_url: "/p/sea-to-summit-reactor-midweight-liner" md_url: "/p/sea-to-summit-reactor-midweight-liner.md" locale: "en" market: "eu" currency: "EUR" price: 63 price_formatted: "€63" availability: "InStock" item_condition: "NewCondition" category: "Sleeping bag liners" category_path: "/c/sleep/sleeping-bag-liners" breadcrumbs: - name: "Home" url: "/" - name: "Sleep" url: "/c/sleep" - name: "Sleeping bag liners" url: "/c/sleep/sleeping-bag-liners" - name: "Sea To Summit Reactor Midweight Liner" url: "/p/sea-to-summit-reactor-midweight-liner" last_updated: "2026-07-08" --- # Sea To Summit Reactor Midweight Liner Brand: Sea To Summit · Category: [Sleeping bag liners](/c/sleep/sleeping-bag-liners.md) Liner size: Long, Regular, Short · Material: Thermolite® Pro, Thermolite® EcoMade · Material composition: Polyester ## Offer - Price: €63 - Availability: In stock - Condition: New - Buy on the website: [HTML product page](/p/sea-to-summit-reactor-midweight-liner) ## Description The Sea to Summit Reactor Midweight liner boosts your sleeping bag's thermal comfort by up to 6°C (11°F). It's stretchy, soft to the touch, and has clever hand openings so it won't restrict your movement at night. The liner also protects your sleeping bag from sweat and dirt, extending its lifespan. ## What makes this product special? Up to 6 °C of extra warmth and total freedom of movement in a practical package. material – Thermolite® Pro and Thermolite® EcoMade (100% recycled), increases thermal comfort by up to 6 °C, mummy shape, drawcord on the collar and hood, integrated arm openings and shoulder snaps for attaching to Sea To Summit sleeping bags, odor control via HeiQ Fresh FFL treatment, travel bag (11.5 x 19 x 11.5 cm) ## Specifications The Sea To Summit Reactor Midweight Liner is a sleeping bag liner that **adds thermal comfort** while also serving as **protection for your sleeping bag against sweat and dirt**, helping extend its lifespan. According to the manufacturer, it increases thermal comfort **by up to 6 °C**, all while keeping a good weight and packability. In sufficiently warm conditions, or in mountain huts and hotels, you can use the liner on its own. Its advantage over down is that it retains its properties even when damp. Unlike a sleeping bag, you can simply toss the liner in the washing machine. The liner's **mummy shape** naturally follows the curves of the human body and **fits beautifully inside a mummy-shaped sleeping bag.** You can easily adjust the collar and hood using the **drawcord**. A great feature is the **integrated arm openings** and shoulder snaps, which let you clip the liner onto Sea To Summit sleeping bags. That way you can keep the hood cinched snugly around your head while still having your hands free for reading or cooking. The package also includes a handy **travel bag**, which lets you pack the liner down into a compact bundle measuring **11.5 x 19 x 11.5 cm.** ## Materials The Reactor Liner sleeping bag liner is made from **Thermolite® Pro** and **Thermolite® EcoMade** (100% recycled). These are synthetic hollow fibers that use trapped air in their chambers to boost thermal-insulating properties. Thermolite® Pro additionally contains special **ceramic pigments**, which absorb infrared radiation from your body and reflect it back to you. Both materials are highly **stretchy**, excel at **quick drying**, and are very **pleasant to the touch**. The liner retains its great properties for a long time, even in more demanding conditions. Sea to Summit liners are treated with **HeiQ Fresh FFL technology**, which contains no biocides and is highly effective at **controlling odor**. It uses a bio-based amino sugar polymer to neutralize body odor. This means the liner doesn't need to be washed as often, which helps extend its lifespan. If you're after a lighter, less warm liner, check out the [Reactor Lightweight Liner](/p/sea-to-summit-reactor-lightweight-liner). ## Specs - Color: Yellow - Liner size: Long, Regular, Short - Material: Thermolite® Pro, Thermolite® EcoMade - Material composition: Polyester - Packed dimensions: Ø 11,5 x 19 cm - Weight: 365 g - Brand: Sea To Summit ## Variants - Sea To Summit Reactor Midweight Liner - Long · SKU 053303 · EAN 9327868169818 · €71.40 · In stock · Long, Yellow - Sea To Summit Reactor Midweight Liner - Regular · SKU 053302 · EAN 9327868169825 · €63 · Out of stock · Regular, Yellow - Sea To Summit Reactor Midweight Liner - Short · SKU 053301 · EAN 9327868169832 · €63 · Out of stock · Yellow, Short ## Related - [Big Agnes Alpha Direct Fleece Sleeping Bag Liner](/p/big-agnes-alpha-direct-fleece-sleeping-bag-liner.md) - [Sea To Summit Spark II](/p/sea-to-summit-spark-2.md) - [Sea To Summit Silk Blend Liner Mummy](/p/sea-to-summit-silk-blend-liner-mummy.md) - [Sea To Summit Spark III](/p/sea-to-summit-spark-3.md) - [Sea To Summit Reactor Fleece Liner Mummy](/p/sea-to-summit-reactor-fleece-liner-mummy.md) - [Warmpeace Viking 600](/p/warmpeace-viking-600.md) - [Sea To Summit Breeze Liner Mummy](/p/sea-to-summit-breeze-liner-mummy.md) - [Therm-a-Rest Z Lite](/p/therm-a-rest-z-lite.md) ## Shipping and returns - [Shipping and payment](/shipping-payment) - [Returns](/return-order) ## Images - ![Sea To Summit Reactor Midweight Liner](https://media.gramino.com/medusa/STS-Reactor-Midweight-Liner-1-01KX1BSWXS8MNPNVZWCFY6V0Y0.jpg) - ![Sea To Summit Reactor Midweight Liner](https://media.gramino.com/medusa/STS-Reactor-Midweight-Liner-2-01KX1BSX5MPRXBRQYDF9HMHRC5.jpg) - ![Sea To Summit Reactor Midweight Liner](https://media.gramino.com/medusa/STS-Reactor-Midweight-Liner-3-01KX1BSXF2YYHDVN5N6F0EZMSS.jpg) - ![Sea To Summit Reactor Midweight Liner](https://media.gramino.com/medusa/STS-Reactor-Midweight-Liner-4-01KX1BSXRDW9MQACDJ2AFWEX74.jpg) - ![Sea To Summit Reactor Midweight Liner](https://media.gramino.com/medusa/STS-Reactor-Midweight-Liner-5-01KX1BSY4MJSM9EM9H75XNJJ3K.jpg) ## Identifiers - SKU: 053303 - EAN: 9327868169818 - Handle: sea-to-summit-reactor-midweight-liner - Brand: Sea To Summit This product is also available as [HTML](/p/sea-to-summit-reactor-midweight-liner). 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