Shopping cart

  • No products in the cart.

Ultra-Sil Dry Sack

Pack organization and water resistance all in one

$15.95 – $34.95

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 14ºF means a man should be comfortable down to air temperatures of 14ºF. The same bag will also have a Comfort limit, in the realm of 27°F, so a woman would be comfortable down to an air temperature of 27ºF. 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 Ultra-Sil™ Dry Sack won the sought-after Backpacker Editors' Choice award in 2006 and is still the ideal dry sack for backpacking and travel. Made with lightweight, waterproof 30D Ultra-Sil™ fabric featuring CORDURA® yarns it's the perfect choice for modular packing to organize your gear inside your backpack or duffle like a pro. The semi-translucent fabric means that it’s easy to see what’s in each dry bag, and if you're really organized you'll make use of multiple color options to find things even easier. Other features include a non-wicking hypalon roll-top closure, a round base for ease of packing and taped seams to keep moisture out. An excellent choice for lightweight backpacking, cycle touring and travel.

Read more about which dry bag is right for you HERE

Technical Features

30D Ultra-Sil®

An incredibly lightweight yet durable fabric used in a large number of Sea to Summit products. This 30 denier Nylon is made with CORDURA® yarns for strength, woven into a ripstop pattern. Two versions of the fabric are used:

  • water-resistant products (such as the Ultra-Sil™ Stuff Sacks) are siliconized on both sides for ultimate packability
  • waterproof products (such as the UltraSil™ Dry Sack are) siliconized on the outside and PU-coated on the inside to allow seam taping.

Both versions have a hydrostatic head greater than 2000mm – which makes them more than adequately waterproof for the types of environments they are intended for.


Cordura® is a special type of nylon yarn used for its strength. These yarns are used in two different product areas:

>  In the siliconized Ultra-Sil™ fabrics used in Ultra-Sil™ Dry Sacks, Stuff Sacks, Compression Sacks, Pack Covers, Travelling Light and Travel Essentials products
>  In the foot section of the extremely tough eVent® Quagmire Gaiters.

    Tech Specs

    Product Details

    Best Use
    Backpacking, Hiking, Bike Packing & Travel
    Waterproof durable roll-top closure
    30 Denier Ultra-Sil Cordura® nylon
    Length - measured with roll-top closure openVolume - measured with closure rolled 3 times
    Repair Buckle Size
    5/8in | 15mm (2-Pin)
    Cylindrical with an ideal height-to-width ratio for easy packing
    Perfectly adequate for dry storage inside a backpack, bike bag or duffle
    1 LITER
    2 LITER
    4 LITER
    8 LITER
    13 LITER
    20 LITER
    35 LITER
    4.9 x 9.4 in / 11 x 24 cm
    0.7 oz / 20g
    5.1 x 11.4 in / 13 x 29 cm
    0.8 oz / 23g
    5.9 x 13 in / 15 x 33 cm
    0.9 oz / 26g
    6.7 x 18 in / 17 x 46 cm
    1.1 oz / 30g
    8.6 x 21 in / 22 x 53 cm
    1.4 oz / 40g
    10 x 24 in / 25 x 61 cm
    1.8 oz / 50g
    12 x 27 in / 30 x 70 cm
    2.3 oz / 65g


    Scroll To TopScroll To Top