A sleeping bag and mat are essential for a comfortable sleep when camping or hiking in a tent. A mattress that provides ample heat and insulation from the ground and provides cushioning is the key to a comfortable sleep
In addition, I often use an inner sleeping bag to further improve the quality of my sleep
Inner sleeping bags are convenient items that not only promote a comfortable sleep due to their soft feel, but also have many additional functions such as boosting heat retention and protecting the sleeping bag from dirt
SEA TO SUMMIT 's inner sleeping bag the Reactor Liner Mummy with Drawcord , and found it to be an extremely useful item that not only functions well as an inner sleeping bag but also goes beyond its intended use, so I would like to review it here.
table of contents
Key Features of the SEA TO SUMMIT Reactor Liner Mummy with Drawcord
This mummy-style inner sleeping bag is made with Thermolite® Pro, a material that absorbs and reflects infrared rays emitted by the body. It can increase the warmth of a three-season sleeping bag by up to 6%, so it not only adds warmth to the sleeping bag but can also be used as a sheet to protect the sleeping bag itself from stains. The highly stretchable fabric allows for unrestricted movement within the sleeping bag, and it can be used alone in hot weather and as an inner layer in cooler weather, making it suitable for year-round use
Recommended points
- Comfortable to the touch even on bare skin
- Highly stretchy material that won't restrict movement
- Thin yet provides excellent heat retention
- By being able to expose your arms and legs, you can walk and cook while inside the inner sleeping bag
- Lightweight and compact
- Easy to wash in the washing machine
Points of interest
- The drawcord tightens the foot box and makes it feel flat
Main specifications and evaluation
| item | SEA TO SUMMIT Reactor Liner Mummy with Drawcord |
|---|---|
| weight | Compact: 266g Standard: 283g |
| size | Compact: 80cm wide x 198cm long Standard: 80cm wide x 216cm long |
| Storage size | Height 11 x Width 15 x Depth 7 cm |
| material | 100% Polyester, 50% Thermolite® Pro/50% Thermolite® EcoMade |
| Reference price (tax included) | Compact: 10,780 yen Standard: 11,550 yen |
| Outdoor Gearzine Review | |
| Comfort | ★★★★☆ |
| Thermal insulation | ★★★☆☆ |
| weight | ★★★☆☆ |
| Storage capacity | ★★★★☆ |
| Ease of use | ★★★★★ |
| durability | ★★★☆☆ |
| versatility | ★★★★★ |
Usage Impressions
Comfortable to the touch even against bare skin, with highly stretchable material for zero discomfort
As mentioned at the beginning, the role of an inner sleeping bag is to boost heat retention, protect the sleeping bag itself from sweat and sebum stains from the human body, and promote comfortable sleep
Many standard sleeping bags use water-repellent fabric, which feels smooth to the touch when dry, but can become sticky or clingy when sweaty. The Reactor Liner Mummy With Drawcord feels incredibly soft and completely comfortable against the skin. It feels just like regular clothing, and even when it touches your skin, it's not at all noticeable (in fact, it's quite comfortable). Made with highly stretchable 100% polyester material, it won't restrict movement while you sleep, and even if it does get wet, it dries quickly, making your sleeping bag comfortable.
It's so stretchy that you can even sit inside it
Thin yet provides excellent heat retention
The material is a 50% Thermolite® Pro and 50% Thermolite® EcoMade blend. This Thermolite® is a fabric developed by Lycra, an American company, and is not only soft to the touch and quick-drying, but also has excellent heat retention
The Reactor Liner Mummy With Drawcord is the thinnest of the three warmer models in the Reactor series. Though the fabric is almost see-through, its insulation power exceeds its appearance. Once inside, you'll feel a gentle warmth and definitely feel the boost in insulation. Because it's primarily an inner sleeping bag, it's dangerous to rely too heavily on its insulation, but according to official figures, it can improve the warmth of a three-season sleeping bag by up to 6%.
the Reactor Liner Mummy with Drawcord is recommended for winter and other cold weather, it can also be used on its own in summer. While it's not recommended for use alone in mountainous areas, even in summer, it can be used comfortably on its own when thru-hiking low-altitude trails or camping, where a sleeping bag isn't needed.
About the heat retention of the Reactor Liner Mummy With Drawcord
In actual field testing, we felt that the Reactor Liner Mummy With Drawcord
This is merely a guideline based on the author's personal experience, as it varies greatly depending on the season, but for example, when I used a sleeping bag with a comfortable temperature of -5°C in an environment where the temperature was -5°C, I was able to stay warm, but when I used a sleeping bag with a minimum operating temperature of 5°C in the same environment where the outside temperature was -5°C, I felt cold, so it is important to keep in mind that this is an item that will only be effective when the heat retention of your main sleeping bag is guaranteed
I personally believe that this item will increase the comfortable temperature range by 3-5°C. It is important to understand that it does not improve the warmth of a sleeping bag beyond the lower limit of its usable temperature range
Lightweight, compact and highly portable
The weight including the storage bag is just 296g, less than 300g
The standard size weighs just 283g and can be stored very compactly, making it easy to carry. Adding 283g to your main sleeping bag boosts its heat retention, provides protection for the sleeping bag, and provides a comfortable feel, which is a major benefit. It's also a convenient size to take when staying in a mountain hut, not just a tent. While a prepared futon is usually provided when staying in a mountain hut, using a sheet will provide you with even more peace of mind
The calculated temperature increase of "6%" is difficult to understand
One thing that bothered me was that the 6% increase in warmth for a three-season sleeping bag was a bit confusing. Because it's dangerous to rely on the warmth of an inner sleeping bag in mountainous areas during the winter, the assumption is that the boost in warmth is only possible if the main sleeping bag is properly matched to the environment. However, since the 6% increase is based on a sleeping bag that has a temperature rating, it's difficult to calculate, and it's hard to know how much warmth you can expect from using an inner sleeping bag
I also used the older Thermolite Reactor model, which clearly stated the maximum temperature increase as 8°C, making it easy to use as a guide. While I understand that it's dangerous to easily trust a clear number when it's displayed, as a user I felt it would be easier to understand if the heat retention capacity was displayed in the same units, and it would also be easier to use as a guide when choosing equipment
The 8°C increase in the previous model was the maximum temperature increase and is not a guaranteed figure. The author concluded that the new Reactor Liner Mommy With Drawcord can also be expected to achieve a stable increase of 3 to 5°C from the comfortable temperature after multiple uses.
The ability to expose your arms and legs makes it convenient to walk and cook while inside the inner sleeping bag
When I saw the Reactor Liner Mummy with Drawcord, the Reactor Liner Mummy with Drawcord allows you to put your arms and legs out, so it feels more like you're "wearing" the sleeping bag rather than just getting into it. Once you've finished setting up your tent at the campsite, you can keep it on until you go to sleep.
The high stretchability means you can sit cross-legged without any problems, and you can cook and eat with both hands free. You can even walk around in it by rolling it up to your waist, so you can even wear it to the toilet
Some people may disagree about how it looks when worn, but I was able to stay comfortable at the tent site because I didn't have to take off my inner layer every time I got out of my sleeping bag
One thing that bothered me was that the drawcord at the feet can be tightened while sleeping, which can be a little uncomfortable. The fabric itself is supple and comfortable, but when tightened by the drawcord, it becomes stiff and feels lumpy. This can be solved by leaving the drawcord open when you're not worried about the cold, but in situations where you're worried about the cold and want to be fully prepared and maximize your warmth, it can be a bit of a nuisance (although not so much that it bothers you and causes stress that keeps you up at night). Incidentally, there are models without drawcords available for those who don't like the discomfort around the feet
When the drawstring is tightened, it becomes like a lump and is a bit bothersome when sleeping
The different colored entrances make it easy to enter
It features a distinctive yellow color that stands out, but there is no zipper, so you basically have to slip it on from the head (you can also put it on from the feet up), and the different color of the entrance makes it easy to identify where the entrance is, so there is no hassle when getting in. There are buttons in areas where you can reach your hands, so you can get in and out easily by unbuttoning them. It's a small detail, but you can see that it has been designed to be easy for the user to use
The main color is yellow and the entrance is black, making it easy to find
Easy to wash in the washing machine
An inner sleeping bag not only protects your main sleeping bag from dirt caused by sweat and sebum, but it can also be easily washed, which is a hygienic benefit. While your main down or synthetic sleeping bag can be washed, they are heavy and require a lot of effort to wash after each use. In contrast, the Reactor Liner Mummy With Drawcord is lightweight and can be tossed in your home washing machine on the regular cycle. Even if you wash it after each use, it's not a hassle and you can always use it in a clean condition.
Summary: Adding this to your main sleeping bag will take your sleep in the mountains to the next level!
Although lightweight, an inner sleeping bag is not something you'll need, and it may be considered a luxury item when hiking, climbing, or traveling, where you're carrying all your essentials. However, considering the comfort, convenience, and ease of use it offers, it's well worth adding to your gear. Why not take your mountain sleep quality to the next level with the Reactor Liner Mummy With Drawcord
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Yosuke
A person who travels around with just one backpack, with the motto of "as light as possible" without causing inconvenience
From spring to autumn, I go fishing in mountain streams in pursuit of char deep in the mountains. I hike the mountains in search of spectacular views that cannot be seen from the ground. I camp to relax by a bonfire. I snowboard to experience the feeling of floating in the silvery white mountains
A freelance writer with over 20 years of outdoor experience who enjoys the outdoors in his own way all year round. Based on his experience writing articles for over a dozen outdoor web publications, he will share his own experiences and the best tools he has used
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