SKU: 34114421068

Sea To Summit Reactor Lightweight Liner - Regular

Sale price$62.96 Regular price$69.95
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USA
  • USA
  • CAN

Ships within 48 hours · Estimated delivery Aug 19 - Aug 24

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For Your Every Summer RSVP, with Code: SUMMER15

Description

Sea To Summit Reactor Lightweight Liner - RegularOptimized for minimal weight and maximum warmth, the Reactor Lightweight enhances sleep system performance with advanced Thermolite Pro fabric, which uses infrared absorbing ceramic pigments and hollow core fibers to trap body heat. Adding up to 4C 7F of warmth with minimal bulk, its ideal for ultralight expeditions. Stretch knit fabric and articulated arm openings ensure unrestricted mobility. Treated with HeiQ Fresh odor control, its quick drying,

Optimized for minimal weight and maximum warmth, the Reactor Lightweight enhances sleep system performance with advanced Thermolite® Pro fabric, which uses infrared-absorbing ceramic pigments and hollow-core fibers to trap body heat. Adding up to 4°C|7°F of warmth with minimal bulk, it’s ideal for ultralight expeditions. Stretch-knit fabric and articulated arm openings ensure unrestricted mobility. Treated with HeiQ Fresh odor control, it’s quick-drying, machine washable, and helps prolong your sleeping bag’s lifespan by reducing wash frequency.

Best Use: Backpacking, Cycle touring, Paddle touring

Features

  • Lightweight and insulative, Thermolite® Pro technology with hollow-core fibers and infrared-absorbing pigments enhances warmth with minimal pack size
  • Freedom to Move – Stretch-knit and shaped arm openings allow unrestricted movement, providing natural comfort throughout your sleep
  • Technical Shape and Hood – Ergonomic design with a fitted hood delivers optimal warmth and comfort without extra weight or bulk
  • Fits any sleeping bag - Stretch fabric means the Reactor Liner fits any shape of sleeping bag
  • Stay Fresh Longer – HeiQ Fresh odor control technology keeps the liner fresh after extended use
  • Sleep System Integration – Snap connectors at the shoulders easily pair with Sea to Summit sleeping bags for quick, hassle-free entry and exit
  • Easy to Keep Clean – Machine washable construction simplifies care and reduces wear on your sleeping bag over time
  • Lower Impact Materials – Crafted with certified recycled fibers and bluesign APPROVED materials to minimize environmental impact

Tech specs


Regular
Weight 9.0oz
Dimensions 76.0 x 31.5 in
Packed Size 3.9 x 7.1 x 3.9 in

Material(s)
100% Post-Consumer Recycled Polyester; Stuff Sack: 100% Polyester

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 34114421068

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4.3 ★★★★★
Based on 6 reviews
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Product Reviews
J
Verified Purchase
john jeffrey elliott
Omaha, US
★★★★★ 1
TOO SMALL
Size: Medium, Color: Blue
Nice socks, but they are way too small. Says they fit size 6 - 10. I kept 3 ( I wear size 8) and gave 3 to my daughter (size 8.5). We both agreed that they were just too small.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 12, 2026
M
Verified Purchase
Mar Gee
Houston, US
★★★★★ 5
Style and comfort
Size: Medium, Color: Black
Exactly what I was looking for. Style and sock thickness and comfort.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on December 14, 2025
A
Verified Purchase
Amazon Customer
Belleville, US
★★★★★ 5
Comfortable
Size: Medium, Color: Blue
So comfortable! They stay up perfectly love love love
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on December 7, 2025
G
Verified Purchase
Glass
San Leandro, US
★★★★★ 5
I stay on your foot they don’t slip in your shoe
Number of Items: 3, Color: White/Neutral (3-pairs), Size: Medium
This is the only socks I wear Under Armour because they stay in place I wear a size 8, but they’re more comfortable with a large instead of a medium, but I wear both because I have them already and you can pull them to stretch them out a little bit
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 12, 2026
L
Verified Purchase
Lauren
Natrona Heights, US
★★★★★ 5
Great fit, truly doesn’t slide off heel
Number of Items: 3, Color: White/Neutral (3-pairs), Size: Medium, Number of Items: 3, Color: White/Neutral (3-pairs), Size: Medium
I’ve scoured all the lands looking for a no-show sock that was 1) thin, 2) quality, soft, breathable material, 3) didn’t dig into my feet/heels, 4) doesn’t shrink, and most importantly 5) stays on the back of my heel without a bulky non-slip rubber piece and these check all the boxes! Perfect for low profile women’s work shoes like Keds, etc. Not low enough for most flats though. I wear a women’s size 9.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 19, 2025

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