Sea To Summit has expanded their ultralight Spark and women’s specific Flame Series of sleeping bags. More temperature ratings, more sizes, and one of the lightest 50°F down liner bags out there. Check out all the details here…

Posted by Miles Arbour

In case you missed it, I reviewed the Sea To Summit Spark SP I sleeping bag in 2017, and was thoroughly impressed. To summarize, it weighed in just over 12oz and packed down smaller than any down sleeping bag I had used before. The model I tested was rated for 46°F (8°C), so it was relegated to summer and early shoulder season use, but for $299 I think it is money well spent. At that time, the Spark series was limited to three different temperature ratings, in regular and long sizes.

For 2020, Sea To Summit has considerably expanded the lineup. Not only did they add more temperature ratings, increasing the total number of bags from three to five, but they added an entirely new women’s specific lineup, the Flame Series. From ultralight liner bags rated for 55°F (12°C) to mid-winter bags for 5°F (-15°C), the Spark and Flame Series take a no-frills approach to lightweight sleeping bags. Check out the details on both series below.

Sea To Summit Spark Series

The Spark series from Sea To Summit is designed for the performance-minded backcountry user. All of the bags use Responsible Down Certified ULTRA-DRY 850+ fill-power down. The shell is made of a ultralight 10D nylon, and the liner of a 7D nylon. For even more weight savings, the 50°F, 40°F, and 28°F have 1/3-length zippers, while the 18°F and 5°F have full-length side zippers. The 50°F and 40°F use a sewn-through baffle construction to save weight, the 28°F has baffles in the torso and sewn through in the leg area, and 18°F and 5°F are fully baffled for better insulation in cold weather. A lightweight silnylon compression bag and storage cube are included with each bag. Every model is available in both a regular (up to 6′) and a long (up to 6’4″). Check out the comparison chart below for complete specs.

  • Sea to summit spark series
  • Sea to summit spark series
  • Sea To Summit Spark Series
  • Sea To Summit Spark Series
  • Sea To Summit Spark Series

Sea To Summit Spark Sleeping Bag Series

Model
Weight oz / grams
Pack Size
Price
Comfort Range

Spark 1 (40°F)
12/340
1.5L
40°-60°F

Spark 2 (28°F)
17.3/490
2.5L
28°-60°F

Spark 3 (18°F)
23.5/665
4.6L
$449
18°-55°F

Spark 4 (5°F)
31/880
6.6L
$529
5°-50°F

Spark 0 (Liner)
7.9/225
0.9L
$229
50°-70°F

*Regular length specs shown, find full spec chart here.

Sea To Summit Flame Series

The Sea To Summit Flame Series shares almost identical specs to the Spark Series, but with a few tweaks to accommodate narrower shoulders and wider hips. It’s worth noting that although Sea To Summit specifically identifies the Flame series as women’s specific, depending on your body and preferences, the Flame series could be great for anyone. The temperature ratings on the Flame series are also slightly warmer when compared to their Spark equivalents, so cold sleepers may appreciate the added warmth. See the full specs below.

  • Sea to summit flame series
  • Sea to summit flame series
  • Sea to summit flame series
  • Sea to summit flame series
  • Sea to summit flame series

Sea To Summit Flame Sleeping Bag Series

Model
Weight oz / grams
Pack Size
Price
Comfort Temp

Flame 1 (48°F)
12.3/350
1.6L
$299
48°F/9°C

Flame 2 (35°F)
17.8/505
2.9L
$349
35°F/2°C

Flame 3 (25°F)
23.5/665
5.3L
25°F/-4°C

Flame 4 (15°F)
31.4/890
7.1L
$529
15°F/-10°C

Flame 0 (Liner)
7.6/215
0.7L
$229
55°F/13°C

*Regular length specs shown, find full spec chart here.

Head over to SeaToSummitUSA.com for all the details.

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