Sea to Summit Spark Ultralight Sleeping Bag: Feather-Light with Ultra-Dry Down

Ultralight, warm, compressible, durable, ergonomic

On my many adventures, I've come across a plethora of gear designed for the passionate wanderer, but few have piqued my interest like the Sea to Summit’s Spark Ultralight Sleeping Bag. When you're trekking in the backcountry, every ounce and every inch matters, and this sleeping bag seems to have been crafted with that very sentiment in mind.

Imagine this: A sleeping bag, weighing merely 12 ounces, that you can compress down to the size of a standard water bottle. It's almost poetic. The lightweight nature doesn't compromise on warmth, as it boasts an 850+ loft ultra-dry down filling, certified by the Responsible Down Standard. It promises warmth, not just for a few treks, but for the long haul.

The Spark isn’t just another sleeping bag; it's a testament to thoughtful engineering. Its technical tapered mummy shape offers the ideal balance between thermal efficiency and a comfortable fit. No one wants to feel like they're wrapped up too tight, and the Spark ensures you have that essential wiggle room without compromising warmth. The vertical chest baffles work diligently to prevent down from shifting as you move, ensuring an uninterrupted, cozy night’s sleep.

One of the nuances that truly stands out is the attention to detail when it comes to moisture protection. The non-PFC treatment shields the high lofting down from the inevitable condensation, ensuring the bag's longevity. Additionally, the Ultra-Sil compression sack made of water-resistant, 30D Ripstop Siliconized CORDURA® fabric is a beautiful touch, reflecting the dedication to durability.

When it comes to accessibility, the 1/3 length ultralight zipper ensures easy ingress and egress while cutting down on weight. And for those seeking variety, this bag comes in an array of temperature ratings, from a brisk five degrees to a mild 40 degrees. Moreover, there's a spectrum of sizes, catering to both regular and tall adventurers, ensuring that everyone can find their perfect fit.

However, beyond the specs, the price tag of $359 might raise eyebrows for some. But for the seasoned trekker who understands the importance of quality gear, this might just be an investment worth making.

In essence, Sea to Summit's Spark Ultralight Sleeping Bag encapsulates what the modern-day adventurer seeks: a blend of cutting-edge performance, thoughtful design, and a commitment to sustainable practices. It's an ode to the spirit of exploration and a testament to the fact that sometimes, the best things come in the most compact packages.


  1. Ultralight Design: Weighing in at just 12 ounces, it's ideal for those who prioritize minimizing pack weight.
  2. High Compressibility: Compresses down to a mere 1.5L, saving precious space in your backpack.
  3. Optimal Warmth: Filled with 850+ loft ultra-dry down, certified by the Responsible Down Standard, ensuring warmth and durability.
  4. Moisture Protection: The non-PFC treatment keeps the down safe from condensation and moisture.
  5. Adaptable Temperature Ratings: Available in various temperature ratings, offering a range suitable for multiple conditions.
  6. Ergonomic Design: Technical tapered mummy shape provides a balance between warmth and comfort. The vertical chest baffles prevent down from shifting, enhancing warmth retention.
  7. Durable Construction: Comes with a water-resistant Ultra-Sil compression sack made of 30D Ripstop Siliconized CORDURA® fabric.
  8. Variety of Sizes: Available in both regular and long sizes, catering to different user heights.


  1. Price: At $359, it might be considered pricey for casual adventurers or those on a tight budget.
  2. Zipper Length: The 1/3 length zipper, while weight-saving, may not be as accessible or convenient as full-length zippers, especially in colder conditions.
  3. Niche Audience: Given its technical design and ultralight nature, it might not be suitable for more casual or less frequent campers who may prefer a more traditional, roomier sleeping bag.
  4. Durability Concerns: While the materials are lightweight for optimal performance, they might be perceived as less durable in rougher conditions compared to heavier alternatives.


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