SEA TO SUMMIT Ember 7C Review: Recommended for hikers who want to make their luggage as light as possible. High quality, ultra-lightweight quilted sleeping bag that combines portability and heat retention

The author walks from the low mountains to the Alps with the motto of "as light as possible."

The weight of equipment excluding food, fuel, etc. is called UL (ultra light) to be less than 5kg, but recently there has been a growing interest in UL, and each brand has added a lineup of lightweight gear.

Some of the items are "edgy" in the pursuit of simplicity, stripping away even the most necessary functions in pursuit of lightness

This time we will introduce the Sea to Summit quilt "Ember 7C", a unique sleeping bag item

Unlike regular sleeping bags, the Ember is a single quilt with no zipper or hood. It may be considered a simple sleeping bag, but the possibilities for use are endless, depending on your imagination. Its versatility is unimaginable from its simple appearance

In this article, I will explain Ember's features and functions, and review my impressions after actually using it

Key Features of the Sea to Summit Ember 7C

Sea to Summit's Ember series is a quilt designed for thru-hikers, cycle tourers, and others who value portability through its lightweight and compact design while also looking for warmth

This sleeping bag is designed to be used in combination with a sleeping mat, and by removing the back section and concentrating the down at the top, it ensures heat retention even with a small amount of down

The down filling is that is RDS certified , and the water-repellent finish overcomes the down's weak point of getting wet.

The fabric is made of ultra-thin 10 denier nylon shell, which is extremely light. The box quilting prevents the down from packing unevenly, so there is no difference in heat retention in different areas

Sea to Summit sleeping bags, including the Ember, have snap buttons that allow you to connect them together to boost their heat retention

Because it is quilted, it has the disadvantage of allowing cold air to easily enter, but to prevent this, there are five connecting loops and drawstrings at the feet and neck to prevent cold air from entering

By using the finest down and ultra-thin fabric, we have achieved a weight of less than 450g. This high-spec quilt achieves both portability and heat retention

Favorite points

• Lightweight and compact for excellent portability
• High versatility possible with a simple single quilt
• Water-repellent 850 + FP premium goose down
• It's primarily for three-season use, but can be used as a boost for warmth in the winter
• Detachable strap for lighter weight if needed

Interesting points

• The mummy style is the winner when it comes to the sense of security it provides as a sleeping bag
• It's difficult to get in and out when connected to a sleeping mat
• If it has a compression function, I wish it was a little larger
• The fact that the mummy-style Spark 7C is lighter

Main Specifications and ratings

Detailed review

Lightweight and compact for excellent portability

When you compare the Ember 7C with a 500ml plastic bottle, you can see how compact it is

Additionally, the included storage bag has a compression function, so you can compress it further if needed, making it even more compact

The 5L bag is so small that it can be difficult to store, but its compact size when packed makes it highly portable

Ember comes in regular and long models, and the regular size is suitable for people up to 185cm tall, giving it a generous size, yet it weighs just 423g, less than 450g

Sleeping bags are one of the heaviest pieces of gear, so if a sleeping bag is this light, it will have a big impact on the base weight of your equipment

High versatility possible only with a simple single quilt

The biggest advantage of quilted pans is their portability, but their versatility is also a unique feature of quilted pans

There are lightweight, compact mummy-style sleeping bags available, so I believe that the versatility of a quilted sleeping bag is actually the reason to choose one

If you connect the sleeping mats together, you can use it almost like a mummy sleeping bag.You can use it as a blanket on your lap when sitting in the tent, or wrap it around your shoulders and snuggle up if it's cold

If it's hot, you can use it like a futon to sleep comfortably without getting stuffy, and if it's cold, you can use the drawcord and straps to cover just the lower half of your body (or you can leave just the lower half exposed)

Quilts that go well with hammocks

I often use hammocks when camping, and quilted sleeping bags are also useful when sleeping in a hammock. Because a hammock is suspended in the air, getting into a mummy sleeping bag can be more difficult than you might imagine (as can getting out), but with a quilted sleeping bag, you can simply lay down and then cover yourself, making it easy

Water-repellent 850FP premium goose down that resists getting wet

The official lower limit temperature for Ember 7C is 7°C

The amount of down used is only 200g, which is not a lot, but the fact that it is able to maintain such high heat retention is due to the characteristics of the quilted design and the ``quality'' of the down

The quilted style removes the back (or the part that touches the ground) which gets crushed when you sleep, and instead brings the down to the top (the part that is not touching the ground).This means that the down is more concentrated than in the regular mummy style, and it provides more heat retention than the amount of down

Another reason is that it uses 850+FP ultra-dry premium goose down, which ensures heat retention even with a small amount of down.

Down typically retains heat by trapping dead air in what is called the loft (expanded feathers). In terms of fill power (FP, bulkiness), which indicates the insulation (quality) per weight, down is considered high quality if it is 600 or above, and the finest if it is 800 or above

The down used in Ember is sustainably sourced (RDS certified) and boasts a loft of 850+ FP

Furthermore, the type of feathers used is goose down, which is larger and of higher quality than duck down.While people tend to focus on FP, which is a numerical representation of quality, the feathers used are also of the highest quality

The down is also water-repellent, making it less likely to get wet (less likely to absorb moisture) than normal, which overcomes down's weakness of getting wet, and prevents its heat-retaining ability from decreasing due to condensation inside the tent or getting wet from sweat

Use with clothing to expand the temperature range

Quilted sleeping bags such as the Ember do not have hoods, so they must be used in conjunction with clothing

What I felt when actually using it was that depending on the clothing you choose, it is possible to use it in environments that are colder than the official minimum temperature

Since tolerance to cold varies from person to person, this is just a guideline, but if you wear only underwear, you will feel cold when the temperature drops below 10°C, but if you wear the down jacket top and bottom and put the hood on, you will be able to wear it in environments below 5°C

By combining Ember with other clothing, you can expand the range of temperatures it can be used in

It's primarily for three-season use, but can be used as a boost for warmth in the winter

The official minimum temperature for the quilt alone is 7°C, and it is suitable for use in the three seasons of spring to autumn. However, due to its lightweight, compact, and highly portable nature, as well as its versatility as a single quilt, it can also be used to boost heat retention in winter

Sea to Summit sleeping bags have snap buttons so you can connect them together, and even if you're using a sleeping bag from another brand, you can improve its warmth by wrapping the quilt around your body

Winter sleeping bags are filled with a large amount of down, which gives them excellent heat retention, but they are also expensive

By combining a three-season sleeping bag with Ember, it can also be used in winter

Detachable strap for lighter weight if needed

All straps used to connect the sleeping mat are fastened with snap buttons and can be removed

This allows you to reduce the number of straps to make the jacket lighter in hotter seasons when you want to prioritize breathability and moisture-wicking over heat retention, and to use all the straps securely in colder seasons to prevent cold air from getting in

When actually using it in the field, it takes more effort to set up than a mummy-style sleeping bag, which you can just place on top of a sleeping mat, but you get used to it after using it a few times, so it only feels like a hassle at first

Summary: "Portability" and "heat retention" are both achieved. And the versatility of the "quilt" means that there are endless ways to use it depending on the user

SEA TO SUMMIT Ember 7C Regular CP 715000 ST81462

created by Rinker

¥47,520 (as of 2026/01/30 17:16:38, according to Rakuten Market - details)

• Amazon
• Rakuten Market
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As sleeping methods become more diverse, such as three-season mountain use, through-hiking on low-altitude trails, and camping in hammocks instead of tents, the versatile quilt is sure to be one of the options

The author feels that the combination of portability and warmth, as well as its versatility, will become the standard for fast-packing sleeping gear for UL hiking, mountain climbing, and other activities in the future

The last thing I want to mention is the price. It's surprisingly low, considering it's an international brand. That said, these affordable prices are only available until August, and once the extraordinary discount campaign by the importer, Lost Arrow, ends, these low prices may also end, so be careful

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