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Basecamp Synthetic Sleeping Bag (20°F & 10°F)


4.6 star rating 12 Reviews

$199.00 – $349.00

Sleeping Bag Temperature Ratings Explained

The EN Rating scale is a scientific test to determine the warmth of a sleeping bag. The test produces a Lower rating (for male sleepers) and a Comfort rating (for female sleepers). Both are listed in the features table on the product page.

A unisex sleeping bag with a Lower limit of 23ºF means a man should be comfortable down to air temperatures of 23ºF. The same bag will also have a Comfort limit, in the realm of 32°F, so a woman would be comfortable down to an air temperature of 32ºF. These ratings require a sleeping mat with an R-Value appropriate for expected ground temperatures – without this, the sleeping bag itself is unlikely to keep the sleeper warm enough.

A variety of factors impact sleeping bag warmth - the above temperatures are merely guidelines, not guarantees. It’s important to think of a sleeping bag, an appropriately insulating sleeping pad and a liner as a sleep system. For example - if you plan on sleeping in nighttime air temperatures of 27ºF / -3°C, choose a bag with a gender-appropriate rating of 23°F / -5°C, plus a sleeping mat with an R-Value of 2.5 to 3, and consider a Reactor thermal liner.


The Basecamp™ Thermolite® synthetic sleeping bag is for those who preferred style of camping is returning to the same campsite each evening to a luxurious and versatile sleep system. Each side of the Basecamp has a full-length side zipper; a third zipper can be found in the foot box zipper. The result is unmatched ventilation and the ability to remove the entire top section to use as a quilt.

WaveLoft™ construction allows the Thermolite® insulation to expand out into air-trapping curves for maximum warmth, and the overall shape of the Basecamp allows you to sleep in any position you choose.

Is this synthetic sleeping bag…?

  • Warm enough for cool weather camping or travel? Yes. The quality insulation and technical construction keep you warm even on chilly nights. The Basecamp 10°F – paired with a high R-Value sleeping mat, like the Comfort Plus Insulated, would be warm enough for Spring through late Fall.

  • Fitted with a sleeve to slide in a sleeping mat? No – it is fitted with something better! The lower part of the Basecamp is fully insulated to avoid cold spots – elasticated straps on the underside attach to a sleeping pad of your choice to form a roomy, cozy sleep system.

  • Suitable for summer temperatures? Yes. The full-length side zippers and foot box zipper can be opened for ventilation or to remove the upper section completely for use as a comforter in really warm weather. And – the main side zippers can be zipped to another Basecamp or many other Sea to Summit sleeping bags.

Learn more about choosing the right sleeping mat to build a perfect sleep system HERE


Best Use

  • Car Camping


  • 3 Season: 20°F (comfort range 20°F to 65°F)
  • 3.5 Season: 10°F (comfort range 10°F to 60°F)


  • A generous shape to allow you to sleep in any position without compressing the down insulation and creating cold spots.


  • Elasticated straps to attach to a sleeping pad of your choice


  • High-quality Thermolite® insulation is loftier and more durable for lasting warmth.
  • Full-length YKK® #5 main side zips and foot box zip provide unmatched ventilation and allow the top section to be removed and used as a comforter.
  • Elasticated straps to secure a sleeping mat underneath the sleeping bag.
  • Shaped hood and zipper draft tubes keep cold out and warmth in.
  • Form a snug sleeping bag for two by zipping to another Basecamp™, Explore™, Ascent™, Trek™, Traverse™, Altitude™, Journey™ or Venture™ sleeping bag.
  • Includes 70D nylon compression bag.

Technical Features

Thermolite® HL-1

Thermolite® HL-1 is part of the family of Thermolite® materials used in Sea to Summit sleeping bags, sleeping bag liners and sleeping mats. HL-1 high loft insulation is a fiberfill constructed with a unique 3D crimp of hollow-core and solid fibers, which provides excellent lightweight warmth with superior durability. The Thermolite insulation lofts up inside the Air Sprung Cells™ of our sleeping mats to prevent convective heat loss from your warm body to the cold ground.

WaveLoft™ Construction

WaveLoft™ is a unique construction technology designed to maximize loft and minimalize insulation weight. Instead of conventional flat layers of insulation (sewn flat on top of each other) or shingle layers (sewn in diagonally overlapping layers), WaveLoft™ creates curved layers which expand out from the shell to trap the greatest amount of air possible at a lower overall weight than existing synthetic insulation constructions.

WaveLoft™ is used on all Sea to Summit synthetic-insulated sleeping bags, regardless of price level.

Tech Specs

Product Details

Best Use
Car Camping
Comes With
Nylon 70D Compression Sack and two (2) elastic mat attachment straps
Thermolite® with WaveLoft™ construction
Shell Fabric
30D nylon with DWR
Zip Options
Full length left side, right side and foot box zipper. This provides more options than we have room to list.
basecamp-synthetic-sleeping-bag-20-f-10-f-regular.svg basecamp-synthetic-sleeping-bag-20-f-10-f-large.svg basecamp-synthetic-sleeping-bag-20-f-10-f-double.svg
Basecamp 2
2lbs 15.3oz / 1340g
8.8 L
M - 14L to 4.5L
6 ft / 183 cm
3 Season
20ºF (Lower Limit)
32ºF (Comfort)
Basecamp 2
3lbs 8.4oz / 1600g
10.9 L
M - 14L to 4.5L
6 ft 4 in / 192 cm
3 Season
20ºF (Lower Limit)
32ºF (Comfort)
Basecamp 2
5lbs 1.1oz / 2300g
16.4 L
XL - 30L to 10L
6 ft / 183 cm
3 Season
20ºF (Lower Limit)
32ºF (Comfort)
Basecamp 3
3lbs 13.4oz / 1740g
12.1 L
L - 20L to 6.5L
6 ft / 183 cm
3.5 Season
10ºF (Lower Limit)
24ºF (Comfort)
Basecamp 3
4lbs 9.4oz / 2080g
16 L
L - 20L to 6.5L
6 ft 4 in / 192 cm
3.5 Season
10ºF (Lower Limit)
24ºF (Comfort)
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