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Sea to Summit Ascent I Sleeping Bag

Sea to Summit Ascent I Sleeping Bag

£283.50 £315.00
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Adaptable, lightweight and comfortable - the Ascent 1 from Sea to Summit is the perfect backpacking bag and is more roomie than traditional mummy-shaped sleeping bags - perfect if you're a wriggler.


Season : 2020W R

Code : AAC1-

Weight : 0KG

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What is the Ascent 1?

Adaptable, lightweight and comfortable - the Ascent 1 from Sea to Summit is the perfect backpacking balance between weight and comfort. The Ascent bags have more room in them than traditional mummy-shaped sleeping bags yet still provide the thermal efficiency needed for all your wild adventure.

What is the Ascent 1 made from?

Insulation: The insulation used in the Ascent is 330g of R.D.S. certified 750FP Ultra-Dry Down. R.D.S stands for Responsible Down Standard and ensures the down is humanely sourced from happy birds which haven't been live-plucked or mistreated. The down is treated with a permanent Nano-level water-repellent polymer treatment to increase the down's performance in damp conditions without adding any weight. This treatment helps to protect the down from external moisture and internal condensation. This does not make this a waterproof bag, but it does mean it will loft better, stay warmer and dry faster than untreated down.

Outer fabric: The outer and inner fabrics in the Ascent is a super-light 20D Nylon fabric. This weight of nylon is what gives you the bags minimal packed size and high breathability.

What is the construction used?

The Ascent uses vertical baffles over the chest section ensuring the down insulation cannot migrate or shift to the outside of the bag whilst you sleep. The side block baffle construction maintains the 60/40 fill ratio. This ratio ensures that more down is kept in the top of the bag for maximum insulation. 

What are the features?

The Free-Flow triple-zip design ensures your sleeping bag retains maximum warmth and efficiency when needed and multiple ventilation options when it’s not. The half zip on the right side of the bag provides freedom of movement for both arms, additional ventilation and means the top third of the bag can be folded down as a mini quilt. The full length, two-way left side zip and separate foot zip transforms the bag into a full quilt for when the temperatures rise.

How does the Ascent fit?

The Ascent has a slightly tapered rectangular shape for the perfect balance of space and adaptable warmth. It's also great if you're a wriggler! The generously sized hood and dual cord adjustment allows for maximum warmth retention whilst the anatomically shaped footbox allows maximum down lofting, minimising heat loss from your feet.


The Ascent is the perfect bag for mountain bivi's, lightweight backpacking, weight conscious travellers and those who prefer having a bit of extra wiggle room around their feet. 

  • Lightweight
  • Tapered rectangular shape
  • 20D Nylon shell and lining fabrics 
  • R.D.S Certified 750FP Ultra-Dry Down
  • Vertical chest baffles
  • Oversized draft tube with anti-snag materials
  • Oversized neck draft tube with a dual adjustment system for even cinching and maximum warmth
  • Generously sized hood and dual cord adjustment
  • Anatomically shaped footbox 
  • Large internal security pocket
  • Compression Bag for compact storage
Care & Advice

How warm a sleeping bag do you really need? We’ve tried to help you by grouping our sleeping bags by their recognised comfort ratings. These are the ratings supplied by the brands that indicate the temperature at which you will remain comfortable whilst sleeping on a good insulated sleep mat. After all, comfortable is what you want to be when it’s cold and wet outside and you’re all tucked up in your nice warm sleeping bag.

We always recommend that you choose your bag according to the coldest conditions you will experience; you can always unzip a bag if it is too warm, but trying to sleep when you’re too cold is just miserable. Bear in mind that that we are all individuals and we all feel the cold differently, and that our own resistance will fluctuate depending a whole load of factors including how much we have eaten, whether we have consumed alcohol, whether we need a wee or what kind of mood we are in!

Sleeping bags do not generate heat they only trap the heat we produce so it is vital that you get into your bag when you are giving off warmth, don’t go to bed when you are cold, have a hot meal or a hot drink or do some brisk exercise to get you nicely warmed up.

Traditionally sleeping bag manufacturers provided their own temperature ratings based on their experience, the products intended end use and the perceived environment. But each brand tested their bags in different ways and it was hard to find a fair comparison between models. So, in 2005 a European standard for sleeping bag temperature ratings, EN 13537, was introduced to give consumers a comparable guide to sleeping bag performance across a range of brands and models. The ratings have four different temperature ratings to give you an indication of the bags performance.

Upper limit: This is the highest temperature at which an average male should experience a comfortable night’s sleep.

Comfort: This is the temperature at which an average female should experience a comfortable night’s sleep. On average women sleep colder than men so this rating is some degrees above the ‘comfort lower limit’ for a man.

Comfort lower limit:  This is the lowest temperature at which an average male should experience a comfortable night’s sleep whilst lying in a curled-up body position. This used to be known as the comfort rating.

Extreme: This is a survival rating where the user is likely to suffer health damage such as Hypothermia. It should be treated with the utmost caution and not be relied on for general use.

However, the EN 13537 European Standard does not apply to down filled sleeping bags with a fill weight of more than 800g; for those bags you will have to rely on the manufacturer's experience and technical expertise, which is often more accurate!

Most reputable brands still use their own rating system alongside EN 13537, for instance the M.E “Good Night’s Sleep” and Rab’s “Sleep Limit”. These ratings are often the most accurate guide to the overall performance of a bag being used by an average outdoor enthusiast. They are based on years of expedition heritage, field trials, technological experience, and constant feedback.

But please bear in mind that all ratings are only a guide and, as mentioned earlier, there are a huge range of factors that can affect your comfort, if you are just not sure it is always wise to go for a warmer model.

The biggest difference you can make to your overall comfort is to use an efficiently insulated sleeping mat. Once you get inside your sleeping bag you instantly compress all the filling beneath you, greatly reducing its efficiency. The use of a quality sleep mat will ensure you are properly insulated from the cold ground and you will of course be a lot more comfortable. Your sleeping bag is only as good as the mat that’s beneath it; we recommend EXPED, ThermaRest or Multimat sleeping mats for comfort and insulation.

Technical Information
Down: 330g, 750+ FP, R.D.S, 90/10 Premium Duck Down
Fabric: 20D Nylon
Shape: Tapered Rectangle
Temp Rating: EN 2°c Comfort to -4°c Lower
Weight: 860g
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Sea to Summit Ascent I Sleeping Bag

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Excellent customer service. Really detailed easy to understand product descriptions on the Trekitt website, and gear reviews on the Trekitt YouTube channel made it so easy to choose the right backpack for me.
Emily - May 2020
Amazing service! Very helpful in regards sizing and what most matched my needs, despite this being done over the internet. YouTube videos of products being examined are very useful also. Would definitely use again, very fast and efficient delivery. Brilliant! Highly recommended!
David R - April 2020
Highly recommend. I usually go to the shop in Hereford as staff are alwasy very helpful and knowledgeable. So this was the first time I have purchased online and the service was just as good as the shop.
Grizzy - April 2020


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