--- product_id: 639990533 title: "Sea to Summit Reactor - Insulated Sleeping Bag Liner" brand: "sea to summit" price: "$218.26" currency: USD in_stock: true reviews_count: 13 category: "Sea To Summit" url: https://www.desertcart.us/products/639990533-sea-to-summit-reactor-insulated-sleeping-bag-liner store_origin: US region: United States of America --- # Compact & lightweight at 386g Adds up to +25°F warmth 50% recycled Thermolite EcoMade fabric Sea to Summit Reactor - Insulated Sleeping Bag Liner **Brand:** sea to summit **Price:** $218.26 **Availability:** ✅ In Stock ## Summary > 🔥 Elevate your sleep game — stay warmer, lighter, and greener on every trek! ## Quick Answers - **What is this?** Sea to Summit Reactor - Insulated Sleeping Bag Liner by sea to summit - **How much does it cost?** $218.26 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.us](https://www.desertcart.us/products/639990533-sea-to-summit-reactor-insulated-sleeping-bag-liner) ## Best For - sea to summit enthusiasts ## Why This Product - Trusted sea to summit brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Snug Mummy Fit:** Technical mummy shape with drawstring hood ensures a cozy, tailored fit that locks in heat. - • **All-Season Versatility:** Transforms your 1-season sleeping bag into a 3-season powerhouse or works solo in milder temps. - • **Eco-Conscious Insulation:** Crafted with 50% GRS-certified recycled fibers, combining sustainability with high-performance comfort. - • **Thermal Boost Technology:** Infrared-reflective Thermolite Pro fabric traps and amplifies your body heat for unbeatable warmth. - • **Travel-Ready Portability:** Ultra-compact stuff sack and machine washable design make it the perfect companion for every adventure. ## Overview The Sea to Summit Reactor Extreme insulated sleeping bag liner uses advanced Thermolite Pro fabric with infrared technology to boost warmth by up to 25°F. Made from 50% recycled materials, it offers eco-friendly insulation without sacrificing performance. Designed in a technical mummy shape with a drawstring hood, it fits snugly inside your sleeping bag or can be used alone in warmer conditions. Lightweight at 386g and easily packable, it’s ideal for backpackers and winter campers seeking versatile, sustainable warmth. ## Description Sea to Summit Reactor series insulated sleeping bag liners can extend the comfort range and improve the personal hygiene of any sleeping bag. Thermolite hollow core fibers are constructed like the hair of a polar bear, effectively trapping heat and providing a luxuriously soft and comfortable feel. The stretch knit fabric provides optimal comfort and ensures that the Reactor fits into any sleeping bag. Plus, the drawstring box offers plenty of ventilation and the versatility of walking around the camp while wearing your liner. Available in three different weights, Reactor technical liners make your existing sleeping bag warmer and more versatile. Regular liner uses hollow-core Thermolite Pro fabric with infrared absorbing ceramic pigments and Thermolite EcoMade fibers. This lightweight fabric adds up to 14 F of warmth to your sleep system. The Extreme Liner features a thicker hollow-core Thermolite Pro fabric to add up to 25 F of warmth to your sleep system. The fleece employs hollow-core Thermolite Pro fibers in a grid pattern to deliver our warmest sleeping bag liner that adds up to 32 F of warmth to your sleep system. Review: Very effective sleeping bag liner, warm and cosy - 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. Review: Well worth the money - Fantastic, far superior to the others I have tried ## Features - MAXIMUM THERMAL BOOST: The Reactor Fleece mummy sleeping bag liner provides added warmth for 1-season sleeping bags and boosts insulation for 3-season bags, making it our warmest sleeping bag liner. Length: 198cm. Width: Shoulders 80cm, Feet 55cm. - SUSTAINABLE & COMFORTABLE: Made from 60% Thermolite All-Season fabric and 40% polyester yarn, this single sleeping bag liner provides optimal heat retention with sustainable construction. The grid fleece material ensures superior comfort and warmth. - EASY CARE & HYGIENIC: Machine washable with no special soap needed, the liner includes a technical mummy shape with a drawstring hood. It also features Heiq Fresh FFL biocide-free odour control, keeping your sleeping bag clean and fresh. - BEST FOR WINTER CAMPING: Ideal for backpacking, camping, and winter camping. It can be used as a standalone sleeping bag in warm weather or sandy environments, making it perfect for a wide range of outdoor activities. - OUTDOOR GEAR THAT ENABLES FREEDOM: Sea to Summit stands as a testament to the boundless spirit of adventure, blending cutting-edge innovation with a deep commitment to empowering individuals to embrace self-reliance in any environment. ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B0CT67SDHF | | Age Range Description | Adult | | Best Sellers Rank | 79,433 in Sports & Outdoors ( See Top 100 in Sports & Outdoors ) 70 in Sleeping Bag Liners | | Brand Name | Sea to Summit | | Closure Type | Drawstring | | Colour | Dark Blue or Black | | Customer Reviews | 4.5 4.5 out of 5 stars (695) | | EU Spare Part Availability Duration | 7 Years | | Fabric Type | thermolite | | Fill Material Type | Thermolite | | Global Trade Identification Number | 09327868158355 | | Item Dimensions L x W | 198L centimetres | | Item Length | 78 Inches | | Item Shape | Mummy | | Item Weight | 417 g | | Manufacturer | Sea to Summit | | Manufacturer Part Number | ASL031031-191902 | | Material | Polyester | | Maximum Height Recommendation | 85 Inches | | Model Number | ASL031031-191902 | | Occupancy | 1pc | | Outer Material Type | Polyester | | Seasons | 3 Seasons | | Size | Compact | | Special Features | Thermal Booster, HeiQ Fresh Odor Control, Stand Up Box with Drawstring | | Sport Type | Camping & Hiking, Backpacking, Hiking | | Temperature Rating | 32F and above | | Thermal Resistance | 32 | | Unit Count | 1.0 count | ## Product Details - **Age range (description):** Adult - **Brand:** Sea to Summit - **Colour:** Dark Blue or Black - **Material:** Polyester - **Occupancy:** 1pc - **Seasons:** 3 Seasons - **Shape:** Mummy - **Special feature:** Thermal Booster, HeiQ Fresh Odor Control, Stand Up Box with Drawstring - **Sport:** Camping & Hiking, Backpacking, Hiking - **Temperature rating:** 32F and above ## Images ![Sea to Summit Reactor - Insulated Sleeping Bag Liner - Image 1](https://m.media-amazon.com/images/I/51qPNmVP9UL.jpg) ![Sea to Summit Reactor - Insulated Sleeping Bag Liner - Image 2](https://m.media-amazon.com/images/I/814fEI0Y8kL.jpg) ![Sea to Summit Reactor - Insulated Sleeping Bag Liner - Image 3](https://m.media-amazon.com/images/I/71nM+r47v6L.jpg) ![Sea to Summit Reactor - Insulated Sleeping Bag Liner - Image 4](https://m.media-amazon.com/images/I/31A+1-F9VtL.jpg) ![Sea to Summit Reactor - Insulated Sleeping Bag Liner - Image 5](https://m.media-amazon.com/images/I/81dtfNHeOgL.jpg) ## Available Options This product comes in different **Style** options. ## Customer Reviews ### ⭐⭐⭐⭐⭐ Very effective sleeping bag liner, warm and cosy *by A***A on 10 January 2026* 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. ### ⭐⭐⭐⭐⭐ Well worth the money *by M***E on 27 August 2025* Fantastic, far superior to the others I have tried ### ⭐⭐⭐⭐⭐ So warm and so perfect. *by J***E on 27 April 2023* Because my house is awaiting insulating, I sleep in mine daily and its so warm and perfect. Breathes well too. ## Frequently Bought Together - Sea to Summit Reactor Insulated Sleeping Bag Liner - Sea to Summit Drylite Towel, Lightweight Camping and Travel Towel - Rainleaf Microfiber Towel Perfect Travel & Gym & Camping Towel. Quick Dry - Super Absorbent - Ultra Compact - Lightweight. Suitable for Trip, Beach, Shower, Backpacking, Pool --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.us/products/639990533-sea-to-summit-reactor-insulated-sleeping-bag-liner](https://www.desertcart.us/products/639990533-sea-to-summit-reactor-insulated-sleeping-bag-liner) --- *Product available on Desertcart United States of America* *Store origin: US* *Last updated: 2026-05-19*