Sea to Summit Airstream Pump Sack
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Airstream Pump Sack
Dry Sack + Sleeping Mat Pump · 2-in-1 · 15D Ultra-Sil
Storage by day, pump by night. The Airstream Pump Sack features a low-profile valve that connects to the multi-function valve on all Sea to Summit sleeping mats — Air Sprung Cell mats and Self-Inflating mats. Used with an Air Sprung Cell mat, two or three cycles are enough to inflate the mat while adding minimal condensation. With a Self-Inflating mat, the pump will "top off" your mat quickly and efficiently. The lightweight 15D Ultra-Sil dry sack is large enough to store clothes or a sleeping bag inside a backpack.
2-in-1 Design
Dry sack by day, sleeping mat pump by night. Saves weight/volume vs carrying a separate dry sack + pump.
Fast Inflation
2-3 compressions fully inflate most STS Air Sprung Cell mats. Top-off mode for Self-Inflating mats.
Minimal Condensation
Pump action adds far less moisture than breath-inflation — protects TPU bladder longevity.
20L Storage
Fits clothes or a sleeping bag inside your pack — replaces a separate dry sack.
Ultralight
1.7 oz / 48 g — barely noticeable in your pack.
Universal Fit
Connects to all STS sleeping mats with multi-function valves — Air Sprung Cell + Self-Inflating.
2-in-1 Storage + Pump Design
The Airstream Pump Sack's defining feature is its dual-purpose design: a fully-functional 15D Ultra-Sil dry sack that doubles as a sleeping mat pump. By day, it stores clothes, sleeping bag, or other gear in your pack. By night, it connects to your sleeping mat and inflates it in 2-3 compressions. Eliminates the need to carry a separate dry sack AND a separate pump.
Low-Profile Integrated Valve
The pump sack has a low-profile integrated valve that connects directly to the multi-function valve on all STS sleeping mats (Air Sprung Cell and Self-Inflating). The valve design is intentionally low-profile so the pump sack can be rolled up small when not in use. The connection is secure — won't disconnect mid-inflation.
15D Ultra-Sil Fabric
The dry sack is made from STS's signature 15D Ultra-Sil fabric — a 15-denier nylon with silicone/PU coating for waterproofness and durability. Ultra-Sil is STS's lightest dry sack fabric line, balancing low weight with reasonable durability for the weight class. Not as tough as the heavier 30D/40D Ultra-Sil variants, but lighter.
Fully Seam-Sealed Construction
The dry sack is fully seam-sealed — every stitch line is taped or welded to prevent water ingress. Important for the pump function too — water that seeps through unsealed seams would be pumped into the sleeping mat, defeating the "minimal condensation" benefit. STS seam-seals the entire dry sack.
20 Litre Volume
The pump sack holds 20 litres of gear — enough for a layer of clothes, a puffy jacket, or a compressible sleeping bag. Sized to fit inside most backpacks as a removable liner or top-pocket organizer. When rolled and clipped, the volume compresses to a very small package (27 × 1 × 17 in rolled).
Fast Inflation (2-3 Compressions)
Per STS: "two or three cycles are enough to inflate the mat." Each cycle = one roll-and-squeeze of the pump sack. The 20L volume is calibrated to deliver enough air per cycle to fully inflate most STS Air Sprung Cell mats (Ether Light XR, Ultralight Air, etc.) in 2-3 cycles. For thicker insulated mats, may require 4-5 cycles.
Why "Minimal Condensation" Matters
Breath vs Pump Inflation
When you inflate a sleeping mat by breath (mouth-to-valve), you pump ~37°C humid air into the mat. As the air cools overnight, the moisture condenses on the inside of the TPU bladder. Over years of use, this moisture can degrade the TPU (hydrolysis) — the same failure mode that the TPU polyether laminate resists. Pumping with the Airstream Pump Sack uses ambient (room-temperature, dry) air, dramatically reducing the moisture that enters the mat. Long-term benefit: extends mat life.
Compatibility
Sleeping Mat Compatibility
The pump sack connects to all Sea to Summit sleeping mats that use the multi-function valve system — both Air Sprung Cell mats (Ether Light XR, Ultralight Air, etc.) and Self-Inflating mats. The connection is direct — no adapters needed. For non-STS mats, the pump sack may not connect (different valve systems).
Use Cases (NEW — MULTI-FUNCTION)
Beyond the pump function, the Airstream Pump Sack works as:
- Dry sack for clothing during wet hikes, kayak trips, boat travel
- Sleeping bag compression sack for transport
- Pack liner for waterproofing pack contents
- Pillow inflation (the pump referenced in Aeros pillow FAQs — turn inside-out to inflate the pillow)
- Camp organization (segregate clean vs dirty clothes, food from non-food)
- Emergency water carrier in a pinch (silicone-lined nylon is water-resistant)
Comparison to Separate Dry Sack + Pump
Weight & Volume Savings
Without the Airstream Pump Sack, you'd carry:
- A separate dry sack (~3-5 oz for a 20L ultra-sil dry sack)
- A separate sleeping mat pump (~2-3 oz for a hand pump)
- Total: ~5-8 oz for both functions
With the Airstream Pump Sack: 1.7 oz for both functions. Savings: 3-6 oz. For ultralight backpackers, that's significant.
Best Use
Primary Use
Sleeping mat inflation (Air Sprung Cell + Self-Inflating mats)
Secondary Use
Dry sack for clothing/gear, sleeping bag compression, pack liner, pillow inflation
Materials & Construction
Fabric
100% Nylon (15D Ultra-Sil — silicone/PU coated)
Seam Construction
Fully seam-sealed (taped or welded seams)
Pump Valve
Low-profile integrated valve — connects to STS multi-function valves
Dimensions & Volume
Weight
1.7 oz / 48 g
Packed Weight
1.7 oz
Packed Size (Rolled)
27 × 1 × 17 in / 69 × 3 × 43 cm (very flat when rolled)
Open Dimensions
25 × 8 × 10 in / 64 × 20 × 25 cm
Volume
20 litres (fits clothes or sleeping bag)
Compatibility
Compatible Sleeping Mats
All Sea to Summit sleeping mats with multi-function valves — Air Sprung Cell mats (Ether Light XR, Ultralight Air, etc.) and Self-Inflating mats
Other Compatibility
Aeros pillows (turn inside-out to inflate via the multi-function valve)
Not Compatible With
Sleeping mats from other brands (different valve systems)
Profile
Brand
Sea to Summit (Australian outdoor gear, founded 1994)
Category
Dry Sack / Sleeping Mat Pump / Multi-Function Storage
Activity
Camping, backpacking, bikepacking, thru-hiking, kayak/canoe, boat travel, wet-weather hiking
Season
Year-round (all seasons)
Cleaning
Rinse with fresh water after exposure to salt, mud, sand, or dirt. For tougher grime, use a mild soap and a soft brush. Avoid harsh detergents that can degrade the silicone/PU coating on the 15D Ultra-Sil fabric. Air dry completely before long-term storage. Do not machine wash or tumble dry — can damage the seam-sealing and the integrated pump valve.
Drying
Air dry only. Open the dry sack fully (don't roll it up damp) and hang or lay flat in a well-ventilated area. Ensure both the fabric and the integrated pump valve are completely dry before storage — trapped moisture can cause mildew and degrade the valve mechanism over time.
Pump Valve Care
Keep the integrated pump valve free of debris — small particles can prevent a proper seal with the sleeping mat valve, causing air leaks during inflation. After each use, disconnect from the mat and visually inspect the valve. Rinse with clean water if needed. Do not use lubricants on the valve — they attract dirt and gum up the sealing surfaces.
Inflation Best Practices
To inflate your sleeping mat: connect the pump sack valve to the mat valve, roll the pump sack from the bottom to push air into the mat, repeat 2-3 times until mat is firm. Don't over-inflate — STS mats are designed to have a slight "give" when you lie on them; over-inflation stresses the welded seams. If the mat feels rock-hard, release a small amount of air via the mat's valve.
Self-Inflating Mat Use
For Self-Inflating mats (which have foam inside that expands on its own when the valve is opened), the pump sack is used as a "top off" tool — first open the mat valve and let the foam expand (10-15 minutes), then use the pump sack to add air until firm. Saves you from having to breath-inflate, which is the typical backup method for SI mats.
15D Ultra-Sil Fabric Care
15D Ultra-Sil is light and packable but not indestructible. Avoid contact with sharp objects (rocks, branches, carabiners, sharp pack straps) that can puncture or tear the fabric. For small punctures: STS sells repair patches (or use any silicone/PU repair tape). For larger tears, the pump sack may need replacement.
Seam-Seal Inspection
Periodically inspect the seam-sealing (especially after heavy use or exposure to extreme cold/heat). Look for any peeled tape or delaminated seams. If a seam starts to fail, contact STS warranty service for repair or replacement.
Long-Term Storage
Store dry and loosely rolled (don't compress tightly for months). The 15D Ultra-Sil fabric can take a compression set if stored tightly rolled for extended periods, affecting the dry sack's ability to fully open. For long-term storage, store loosely folded or in a larger bag.
Puncture Repair
Small punctures in the 15D Ultra-Sil fabric can be repaired with a STS repair patch or any silicone/PU repair tape. Clean and dry the area, apply the patch, and allow to cure fully (usually 12–24 hours) before use. Larger tears or seam failures are not repairable and the pump sack should be replaced.
Travel Tip
The Airstream Pump Sack's 1.7 oz weight and 20L volume make it a great pack organizer and pump combined — store your sleeping bag clothes in it during the day, then inflate your mat at night. For backpackers in wet climates (PNW, Scotland, Iceland), the dry sack function protects clothing from rain even if your pack isn't fully waterproof. For ultralight backpackers, the pump function saves carrying a separate pump AND reduces moisture buildup inside the mat over years of use.
Shipping Policy
Components:
All component items (wheels, drivetrains, suspension, brakes, etc.) ship within 2-5 business days of purchase.
Bicycles:
Complete bikes typically ship within 2–3 weeks due to build, tuning, and inspection times. You will receive tracking information as soon as your order is ready to ship.
Riding Gear & Apparel:
Riding gear and apparel orders (helmets, jerseys, gloves, etc.) ship within 2-5 business days.
Returns & Exchanges:
If you received the wrong size or wish to exchange an item, it must be returned in original condition—unused, uninstalled, and with all packaging intact.
For full details, please see our Refund Policy before initiating a return.
