Sea to Summit Ultra-Sil Compression Sack

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The small version of this sack allows my daughter…

Rating: rated 5 of 5 stars
Source: bought it used
Price Paid: $15.50 on ebay


The small version of this sack allows my daughter to carry both her sleeping bag and pillow in the bottom zipper compartment of her TNF Terra 45 pack. Durable, slippery material squeezes right in.


  • Durable rip stop style codura ultra-sil material
  • Lightweight
  • Slippery material makes putting in/pulling out of pack easier


  • None

Basically, the pictures tell the story:

Here's the Kelty Cosmic Down 20 degree bag in its storage sack.


Here it is in the Sea-to-Summit uncompressed (compared to a Nalgene bottle).


And in its final compressed state.


One of my twins is fairly slight in stature (98 lbs) so her pack is The North Face Terra 45.  When her sleeping bag was stuffed in the sack it came with, it took up the complete zippered compartment in the bottom of her pack. Since she was already limited in space, we decided to try this S2S Ultra-Sil Compression Sack.

(Note: I have a couple of Granite Gear compression sacks I've used over the years but they are made of a heavier weight material and I'm thinking of getting the medium version of this sack for my sleeping bag. The weight difference between the Ultra-Sil and the regular Granite Gear material is quite noticeable.)

I'm interested to see how the material and the seams hold up over time since it is more delicate. The material has a rip-stop type of weave so even if it gets a hole in it I think it will resist getting larger.

Manufacturer's Description

Visit Sea to Summit's Ultra-Sil Compression Sack page.

Retailers' Descriptions

Here's what other sites are saying:

If you need to compress down your gear into the smallest possible space while adding minimal weight, pack it into Siliconized Cordura fabric Ultra-Sil Compression Sack from Sea to Summit.


Trim the weight--and the bulk--of your load with this incredibly light, tough compression sack from Sea To Summit.


Make your sleeping bag, down jacket, or clothing smaller and more compact with the Sea To Summit Ultra-Sil Compression Sack. This ultralight stuff sack features four webbing cinch straps to compress your gear and make more room in your bag or duffel. The flip-top lid prevents straps from tangling and the slick finish makes for easy packing.


Sea to Summit Ultra-Sil Compression Sack FEATURES of the Sea to Summit Ultra-Sil Compression Sack Functional design and lightweight touches of the Ultra-Sil technology is just the right choice for your backpacking adventures. This compression sack compresses to one-third its volume. It's an ideal feature for backpackers who don't want any added weight. Bar tack reinforced stitching on all stress points. This means the Ultra-Sil Compression Sack is super strong as nails. Roughly half the weight of the original Compression Dry Sack. This makes it that much more awesome. Flip-top-lid design prevents strap tangling. Nobody wants any tangling, right? I sure don't. Four straps for even compression. Everybody loves even compression. Pull handle on the bottom for easy release. I totally heart that. SPECIFICATIONS of the Sea to Summit Ultra-Sil Compression Sack Specifications for 3X Small Size: 4 inches by 9 inches Weight: 1.1 ounce Volume: 2.5 L to 1 L Specifications for 2X Small Size: 5 inches by 10 inches Weight: 1.3 ounce Volume: 3.3 L to 1.3 L Specifications for X Small Size: 6 inches by 14 inches Weight: 2.0 ounces Volume: 6 L to 2 L Specifications for Small Size: 7 inches by 16 inches Weight: 2.3 ounces Volume: 10 L to 3.3 L Specifications for Medium Size: 8 inches by 18 inches Weight: 2.7 ounces Volume: 14 L to 4.5 L Specifications for Large Size: 9 inches by 20 inches Weight: 3.3 ounces Volume: 20 L to 6.5 L Specifications for X Large Size: 10.5 inches by 23 inches Weight: 3.8 ounces Volume: 30 L to 10 L

- Moosejaw