Sea to Summit Ultra-Sil Dry Bag
Sea to Summit Ultra-Sil Dry Bag
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The Sea to Summit Ultra-Sil Dry Bag is an ultralight waterproof storage bag built for organizing gear inside a backpack or duffel on backpacking trips, cycle tours, and travel. The 30-denier bluesign-approved Ultra-Sil nylon shell is woven with Cordura yarns, polyurethane-coated on the inside, and rated to a 2000+ mm hydrostatic head, keeping contents dry from condensation and incidental moisture without adding meaningful weight to a load. Six sizes run from 3L to 35L, each available in multiple colors.
Ultralight Organization, Visible at a Glance
The Ultra-Sil Dry Bag's semi-translucent fabric lets a backpacker or traveler identify contents without opening every bag, a practical advantage when digging through a pack at a campsite or trailhead. The slippery outer finish lets the bag slide in and out of a crowded pack easily, and the oval base shape means the bag sits flat and stable rather than rolling away on a tent floor or sloped surface. At 30 g for the 3L and 74 g for the 35L, the Ultra-Sil Dry Bag adds almost nothing to a base weight while keeping a kit organized and separated by category.
Waterproof Construction for Internal Storage
The Ultra-Sil Dry Bag combines four layers of moisture protection: a non-PFAS DWR finish on the outer face sheds surface water, a polyurethane coating on the inside face blocks moisture from penetrating the fabric, taped seams seal the stitching lines, and a non-wicking hypalon roll-top closure secured with a 15 mm Field Repair Buckle keeps the opening sealed. Together these bring the hydrostatic head to 2000+ mm, sufficient for the condensation, rain splash, and incidental moisture a bag encounters inside a pack or duffel. The non-PFAS DWR finish means no PFAS compounds are used in the water-repellent treatment.
Built to Last and Repairable in the Field
The 30-denier nylon is woven with Cordura yarns, which add tensile strength to an otherwise featherweight fabric. The roll-top closure uses a 15 mm Field Repair Buckle designed to be replaceable in the field if it breaks, so a damaged closure does not mean a retired bag. The bluesign approval on the fabric confirms the material meets environmental and safety standards throughout its production.
Features
- 30D Ultra-Sil Cordura nylon: bluesign-approved featherweight fabric with Cordura yarns for added strength
- Semi-translucent fabric: identify contents without opening the bag
- 2000+ mm hydrostatic head: non-PFAS DWR outer finish, PU inner coating, and taped seams
- Non-wicking hypalon roll-top closure: secured with a replaceable 15 mm Field Repair Buckle
- Oval base: prevents rolling on sloped surfaces and packs efficiently
- Slippery outer finish: slides easily in and out of a packed bag or duffel
Specifications
| Size | Weight | Height (top rolled 3×) | Base L × W |
|---|---|---|---|
| 3L | 30 g / 1.1 oz | 20.7 cm / 8.15 in | 14 × 17.1 cm / 5.5 × 6.7 in |
| 5L | 32 g / 1.1 oz | 30.8 cm / 12.13 in | 15 × 17.1 cm / 5.9 × 6.7 in |
| 8L | 39 g / 1.4 oz | 36.8 cm / 14.49 in | 17.2 × 19.1 cm / 6.8 × 7.5 in |
| 13L | 47 g / 1.7 oz | 43.3 cm / 17.05 in | 19.6 × 22 cm / 7.7 × 8.7 in |
| 20L | 58 g / 2.0 oz | 47.3 cm / 18.62 in | 23.6 × 26.9 cm / 9.3 × 10.6 in |
| 35L | 74 g / 2.6 oz | 56.5 cm / 22.24 in | 28.5 × 32.1 cm / 11.2 × 12.6 in |
| Specification | Detail |
|---|---|
| Fabric | 30D Ultra-Sil 100% nylon with Cordura yarns, bluesign approved |
| Buckle material | 100% POM |
| Hydrostatic head | 2000+ mm |
| Closure | Non-wicking hypalon roll-top with 15 mm Field Repair Buckle |
| DWR finish | Non-PFAS (PFC-free) |
| Inner coating | Polyurethane |
| Seams | Taped |
| Base shape | Oval |
| Best use | Backpacking, cycle touring, travel: internal pack or duffel storage |
Who This Is For and Isn't
The Ultra-Sil Dry Bag suits backpackers, cycle tourers, and travelers who want ultralight, modular organization inside a pack or duffel. The translucent fabric and slippery finish make it especially useful for anyone who repacks frequently or needs to locate specific gear quickly in the field.
The Ultra-Sil Dry Bag is not suitable for paddle sports, kayaking, or any watersports use. The featherweight 30D fabric is not designed for the abrasion and puncture hazards of those environments. The bag is also not intended for external mounting or prolonged submersion; those conditions call for a bag with a higher hydrostatic head and more abrasion-resistant fabric.
Common Questions
Can the Ultra-Sil Dry Bag be used for kayaking or paddle sports?
No. The Ultra-Sil Dry Bag's featherweight 30-denier fabric is not appropriate for the sharp or abrasive elements encountered in paddle sports or watersports. The Ultra-Sil Dry Bag is designed for internal storage inside a backpack or duffel, not for external or water-immersion use.
How waterproof is the Ultra-Sil Dry Bag?
The Ultra-Sil Dry Bag carries a hydrostatic head rating of 2000+ mm, sufficient to protect contents from condensation, rain splash, and incidental moisture when stored inside a backpack or duffel. For paddle sports or prolonged external exposure, a bag with a higher hydrostatic head and more abrasion-resistant fabric is the appropriate choice.
What do the Ultra-Sil Dry Bags weigh across the size range?
The Ultra-Sil Dry Bag weighs 30 g (1.1 oz) in the 3L, 32 g (1.1 oz) in the 5L, 39 g (1.4 oz) in the 8L, 47 g (1.7 oz) in the 13L, 58 g (2.0 oz) in the 20L, and 74 g (2.6 oz) in the 35L. All six sizes fall in the ultralight category for their respective capacities.
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