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Sea to Summit Womens Altitude AtI Sleeping Bag

Sea to Summit Womens Altitude AtI Sleeping Bag

£216.00 £360.00
40% off

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The Altitude is a roomy, comfortable and super warm sleeping bag for those who move around in their sleep. The multitude of ventilation options means it's perfect for a wide range of temperatures. 

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Season : ZZZ Discontinued

Code : AAT1-WR-1 Reg

Weight : 0KG

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What is the Altitude?

The Women's specific Altitude is a roomy, comfortable, spacious yet super warm and feature packed sleeping bag for those who move about in their sleep. Despite the roomy interior, the Altitude features a multitude of customisation options to either ventilate or seal in the warmth for greater cosiness.

What is it made of?

Insulation: Insulation is taken care of by 750 fill-power, ULTRA-DRY premium duck down... we know that's a lot of jargon, so lets break it down. 750 fill-power is the highest quality duck down available, meaning a warmer bag without the excessive weight. ULTRA-DRY treated down vastly improves the down's reaction to water without affecting its weight or warmth. Essentially, it will retain 60% more loft and absorbs 30% less moisture than untreated down. RDS certified down ensures that the feathers used in the sleeping bag come from animals which have not been subjected to unnecessary harm. To sum all of that up, it performs better in damp conditions, uses some of the highest quality duck down available and sources it in an ethical and sustainable manner. 

Outer fabric: Surrounding all of this luxurious down is a 20D nylon fabric. This fabric is adequately tough, lightweight and abrasion resistant, making it a perfect all-rounder for this versatile sleeping bag. 

What is the construction used in the sleeping bag?

If you've been waiting for a little nerdiness, this is where it comes in. The area that requires the most warmth, i.e. where your vital organs lie, features vertical baffles in taller, narrower shapes; this prevents the down migrating around the baffle and leaving you with a cold spot during the night. Below this, wider horizonal baffles allow the bag to pack down smaller. Down the sides of the bag, a 'block' construction places 60% of the down on the top of the baffle and 40% below, meaning more down is placed in areas where we lose more heat. Down the bottom of the bag, an anatomically shaped footbox allows the down to loft fully, minimising heat loss around your feet. 

What are the features?

The left side of the sleeping bag features a 1/2 length zip which can be used to ventilate when the temperatures rise, while the right side features a full length zip to make it as easy as possible to escape. This not only gives you multiple ventilation options, but allows you to open both zips and transform the bag into a duvet on warmer nights. You can even zip this sleeping bag into another identical one to create a 'double sleeping bag'... cool right?! Other useful features include draft tubes to prevent heat loss through the zip and around the neck, dual adjustment for cinching in the hood to trap more warmth on cold nights, a large internal security pocket for electronics to stop the battery draining in the night and lastly a super lightweight Ultra-Sil compression bag for compact storage. 

How does it fit?

As you may have picked up by now, the Altitude features a comfortable, roomy fit with plenty of room in the shoulders and around the hips. You're easily able to wear thick layers inside on super cold nights or move about freely on warmer nights.


If you're the sort of person who moves around in their sleep and requires a high performance sleeping bag for backpacking, travelling or general camping above or below the treeline then the Altitude is probably the one for you. 

  • High quality duck down
  • 20D nylon outer fabric
  • Roomy shape
  • Clever baffle design
  • Can open up like a duvet
  • Can attach to another Altitude
  • Plenty of ventilation
  • Women's specific
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

Insulation: 750 Fill-Power RDS Certified, ULTRA-DRY Duck Down

Outer fabric: 20D Nylon

Overall weight: 1080g

Comfort rating: -4°C

Lower rating: -10°C

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Sea to Summit Womens Altitude AtI 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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