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Conquer various climates with the Sea to Summit Ascent -9C Long Down Sleeping Bag. Equipped with 750+ Ultra-Dry Down and QuiltLock system, it's your ultimate outdoor companion.

Conquer various climates with the Sea to Summit Ascent -9C Long Down Sleeping Bag. Equipped with 750+ Ultra-Dry Down and QuiltLock system, it's your ultimate outdoor companion.

Sea to Summit

Sea to Summit Ascent -9C Long Sleeping Bag Green

£427.50 £475.00 10% off
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We estimate this will be ready for despatch to you or collection via Click & Collect on Undetermined
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90-day returns period

We hope that you are perfectly happy with your order from Trekitt, but we understand that you may want to return your purchase. We offer a 90 days return period from the date of purchase, and endeavour to process all returns within 48 hours of receipt.

We do not offer a free returns service. Therefore, all customers are responsible for any postage costs when returning any goods (excluding warranty returns).

For your convenience, follow here to the Royal Mail Returns Portal to arrange return postage for your items. This is not a Trekitt operated service.

The Trekitt Returns Policy Includes...
A 90 day return period and the Trekitt 2-year Common Sense Guarantee.

PPE (Facemasks, Climbing Equipment etc. ), Food Goods, Accessory Cord, Socks & Underwear can only be returned if they have not been worn and/or removed from their original packaging with all swing tags still attached. If there is any sign or possibility that the goods have been used, tampered with or contaminated in any way, then we cannot accept a return on the grounds of consumer safety. Zips are typically not covered under a manufacturer's warranty.

The above does not affect the Consumer Contract Regulations. Click here to read more.

Sea to Summit Ascent -9C Long Sleeping Bag Green

Season:2024S R

Brand:Sea to Summit


Product Ratings

WarmExtremely Warm

We find this suitable for




What is the Sea to Summit Ascent -9C Sleeping Bag?

Unlock the potential of any adventure with the Sea to Summit Ascent -9C Long Sleeping Bag. Boasting 750+ Ultra-Dry Down insulation and a Free Flow Zip System, it offers customisable warmth for hiking, car camping, and other outdoor adventures.

What is it made of?

Insulation:The Sea to Summit Ascent Down -9C Sleeping Bag boasts an insulation system that combines premium materials and innovative technologies to provide superior warmth and comfort in various climates. Featuring 750+ Fill Power, the sleeping bag is filled with responsibly sourced Duck Down treated with Ultra Dry Down treatment. This treatment enhances water resistance, making the sleeping bag suitable for damp conditions. The 750+ Fill Power indicates high loft, meaning that less down is needed to achieve the same level of warmth, ensuring optimal performance without compromising on weight or bulkiness.
Furthermore, the Down used in this bag is RDS certified, guaranteeing ethical sourcing practices, and undergoes independent testing by the International Down and Feather Laboratory (IDFL) to ensure quality and performance.
This sleeping bag also boasts non-PFC (Perfluorinated Chemicals) status. PFCs are commonly used in outdoor gear to provide water repellency, but they have been linked to environmental and health concerns. By opting for non-PFC materials, Sea to Summit ensures their products are free from these potentially harmful chemicals, promoting environmental responsibility and user safety.

Shell and Lining:The shell and lining of the Ascent Sleeping Bag are constructed from 20-Denier Nylon, a material chosen for its durability and performance in outdoor settings. Denier refers to the thickness of the individual fibres in the fabric, with higher denier numbers indicating thicker and more durable materials. In this case, the use of 20-Denier Nylon ensures that the sleeping bag can withstand the rigours of outdoor adventures, including rough terrain and frequent use.

Hood and Footbox:The hood and footbox of the Ascent Sleeping Bag are crafted from 10-Denier Nylon, which ensures that the hood and footbox remain lightweight while providing reliable protection against moisture.
The waterproof-breathable properties of the 10-Denier Nylon fabric allow moisture vapour to escape from the bag's interior while preventing water from penetrating the fabric from the outside. As a result, users can stay dry and comfortable even in damp or humid conditions, ensuring a restful night's sleep regardless of the weather.

What are its features?

Sea to Summit's Free Flow Zip System offers unparalleled temperature regulation and adaptability. It allows for multiple zipper configurations, enabling users to adjust their sleeping bag for various climates and personal preferences. Whether you need maximum ventilation or enhanced insulation, this system can easily be tailored to your sleeping needs.
With three configurations available, including a quilt, two bags coupled together, or a standard setup, the Free Flow Zip System offers versatility and adaptability to suit changing circumstances. This flexibility ensures that your sleeping bag can evolve with your adventures, providing comfort and warmth in any situation.
The QuiltLock system further enhances the versatility and thermal performance of this Sea to Summit sleeping bag.
By securely attaching a quilt to the sleeping bag using snap locks located at the shoulder and foot end, the QuiltLock system transforms a three-season bag into a four-season solution.
The system provides added insulation and warmth, particularly in colder conditions, ensuring you can stay comfortable and protected from the elements.
This sleeping bag comes in a relaxed mummy fit. This design ensures high thermal efficiency while providing freedom of movement for a more comfortable sleep experience.
The Ascent sleeping bag features a baffle construction. It combines vertical and horizontal baffles with box wall construction to maximise warmth and minimise cold spots. This innovative design ensures the even distribution of insulation, preventing heat loss and creating a cosy sleeping environment.
The Relaxed Mummy Fit strikes a balance between snugness and spaciousness, allowing users to enjoy the benefits of a traditional mummy bag without feeling constrained. Whether you're a side sleeper or prefer to move around during the night, the Relaxed Mummy Fit ensures that you stay warm and comfortable throughout your outdoor adventures.
Thanks to a down-filled draft tube along the top of all zippers, this sleeping bag provides enhanced insulation and protection against cold drafts. This draft tube also ensures that heat is retained within the sleeping bag while preventing chilly air from seeping through the zipper, maximising warmth and comfort during outdoor adventures. The down-filled draft tube effectively seals the sleeping bag, minimising heat loss and ensuring a cosy night's sleep, even in colder conditions.
The Sea to Summit's Ascent Sleeping Bag also features an integrated hood and collar. The hood is spacious enough to accommodate a regular Sea to Summit pillow, providing added convenience and comfort during sleep. Additionally, the fitted front draft collar prevents heat loss by sealing in warmth and blocking cold drafts.


  • Free flow zip system
  • QuiltLock system
  • Non PFC
  • Relaxed mummy fit
  • Baffle construction
  • Fitted draft collar
  • Generous hood
  • Draft tube
Technical Information

Materials: 750+ FILL Power Ultra-Dry Down, Recycled 20-Denier Nylon
Size: Long
Weight: 1157g
Fill Weight: 617g
Temperature rating: comfort: -2°C | 29°F, lower limit: -8°C | 18°F
Max User Height: <198m
Compressed Size: 13L
Zip: Full length #5 primary, 1/2 length #5 secondary, #5 footbox
Bag, Quilt, Pillow Integration: Compatible with Unisex Sea to Summit bags, STS quilts, and fits Sea to Summit Regular Pillow in hood

Sizing Information
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