This article is based on an article from the Japanese edition of Engadget and was created using the translation tool Deepl.

Nearly a year after raising over 60 million yen in one week, Sony's REON Pocket, or "Wearable Cooler," is now available to the public.

REON Pocket is a device that uses Peltier elements that electrically transfer heat to cool or warm the human body.

It is attached to the neck area of the back with the special inner wearer. This makes it inconspicuous from the outside and does not block your hands. Instead of sending a breeze, the cold part is applied to the body's surface to cool it directly, so you can use it even if you are wearing a shirt and jacket.


According to Sony, in an experiment at 30 degrees Celsius and resting conditions, the REON Pocket was used to create a 5 After five minutes, the surface temperature of the body dropped 13 degrees Celsius at the contact point. Due to the Peltier element's ability to reverse the heat transfer, it can also warm up the human body, and in winter, it can also be used as an electric body warmer.

When I tried the prototype, it worked surprisingly well in the early spring, when it was hot and sweaty during the day but chilly at night. In summer, you can use it as a cooling mode on the move or outdoors, and when it gets cold in an air-conditioned room, you can use it as a heat source, which is an advantage not found in other cooling/warming products.


It is equipped with Bluetooth and using the smartphone app to switch between COOL/WARM and adjust the effect. You can use "My Mode" on your phone to customize the intensity and duration, and alternate hot and cold settings. It is possible. Although it is not a medical health care device, users can use it to warm up somewhere in their body as a beauty treatment. It can also be used as a means of cooling off.

You don't have to have a phone to use it, and you can also use the quick start and auto mode to just turn it on. In auto mode, the system automatically adjusts to the optimal temperature to feel cooler by detecting not only the temperature and body surface temperature (temperature of the cooling module part), but also the user's behavior, such as whether the user is walking or not, using an acceleration sensor. (The technology used in Sony's wearable devices is used for behavior detection.)

As you can feel with coolers and other products, the human body gets used to feeling cold after a little while, even if you touch something cold to some extent, so the basic auto mode works by turning it on and off when you get used to it, and then repeating the coolness again after a while.

The main effect is to feel the coldness that comes when you forget about it, because you're not sweating away all at once with a big fan, or going indoors in an air-conditioned room, or getting cold like you're taking a dip in the water.


The main unit is shaped like a thin mouse, it is equipped with a 4cm square cold section, a heat sink, a thin fan and a battery inside.

Designed to breathe in from the mesh part of the back underside, pass through the heat sink, and exhaust through the slit on the top surface. The collar is effective if you have a little room to spare, though not so much that you feel the heat in your neck.

The Peltier element cools one side of the body and makes the other side hotter than that, so it is a structure that eventually exhausts heat with a fan, but the theory is that it can take heat directly from the surface of the body, and by applying the wind to the metal heat sink that is more efficient than the skin, even with a small capacity battery and a small fan, it can cool more than using it as a fan.

Sony Announces REON POCKET, a Peltier Cold-Warming Device for the Human Body. Applying Thermal Design Technology to Wearables (at the time of the 2019 announcement)

The fan noise is similar to that of a laptop. You'll hear a thumping sound depending on the output, but if it's the lowest output, you won't be able to hear it unless you're in a fairly quiet room and paying attention in the immediate vicinity. You probably won't be able to tell if you're outdoors or on public transportation.


The fact that there are fewer high-pitched, unpleasant sound components than the volume itself, and the fact that it's basically worn underneath the clothing so it's not near your ears, may be another reason why the sound doesn't catch your ear. Depending on the speed of rotation, it is noticeably quieter than a typical air conditioning suit (jacket with fan).

(Although air-conditioned clothing has an air-filled silhouette on the upper body and a large fan in full view, this is a hardcore product whose priority is to make sweat go away anyway. It is a practical product for use at dangerous sites. REON, on the other hand, is casually intended to be cool and warm, so it's different in concept. Just in case.)

In terms of whether or not the people around you can hear it, you might think it's something else, even if you do notice it, because almost no one expects the person in front of you to be wearing a thin fan on the part of your back that you can't see in the first place, so you might not notice it or think it's something else.

Battery life is about 2.5 hours on maximum cooling power and about 2 hours on warmth. Basically, I imagine it's a pinpoint, used when moving around outdoors and right after. This is not a solution for long, hot days in earnest.

A full charge takes about 2.5 hours nominally, and since it cannot operate while charging and feeding power, it is left in use during the day If I forgot to charge it, the battery would be dead when I got home.

The price is 13,000 yen plus tax per unit, and the almost mandatory special innerwear is 1,800 yen each for sizes S/M/L.

You can use what you can hold in your hand, and actually enjoying the cool sensation at your fingertips is effective, but it's a wearable that's made to fit on your back, so it's a complete waste of time without a special inner layer.


There are three sizes of special innerwear, roughly S, M, and L. We recommend checking the size of the innerwear before choosing the one that fits you best. The innerwear is made of functional fibers that are contact cool and quick-drying, so it's important that it adheres to the body and wicks sweat away without creating a layer of air, and because the REON Pocket in the pocket will shift to the back side if it's not fitted, especially at the neck.

(I think it is not impossible to make a T-shirt that can be worn by itself instead of the special innerwear, but it should be difficult to make at least one of them without the actual product because the effect will be halved if there is an air layer in the part where the cold module touches the skin, the air intake part at the bottom of the back needs to be opened, and the size and position of the pockets need to be precise.)


Here's a short summary of my impressions after trying it for a while:

  • The premise is not a replacement for an air conditioner or fan. And it is not something you expect to prevent in a situation where there is a risk of heat stroke.

  • This is a "cool sensation device" that allows you to repeatedly feel the pleasant sensation of a cold object being pressed against you, hands-free, whenever you want.

  • The goal is to reduce heat stress and comfort through a chilly sensation. Practical in that sense. Everyone is amazed at how quickly it cools down as soon as you turn it on.

  • So if you're in a situation where you're a little steamy when you move your body, and you'd like to turn the air conditioning setting down a bit more, you can distract yourself with the cool sensation of the REON Pocket. In this sense, it can be an alternative to your personal air conditioner or fan.

  • As a cooler item, it's also excellent that it's almost invisible from the outside and you can't tell that you're using it (with the fan set to turn on fast in a quiet room, the thumping sound can be heard by anyone nearby).

  • It's not intended to get you through extreme heat without air conditioning, fans, shades or hydration, but on the contrary, it can add a local or temporary coolness when it's still hot enough to do everything else, especially in humid environments where handy fans and the like are useless.

  • Most of all, it's fun to hack your body's sense of cold and warmth externally by manipulating it externally Devices. Such as noticing the difference between temperature and body temperature and subjective hot and cold comfort.

It may sound persistent, but this is not a product that will prevent heat stroke. However, although there is no danger of heat stroke in the situation, it can alleviate the feeling of being hot and painful.

While it's "comforting" in the sense that you can't lower your body temperature like resting in an air-conditioned room or soaking in a water bath, do you think it's unnecessary because it's also a pointless comfort to push a cold drink bottle or coolant against it when it's hot, or do you think it's useful to make it a little easier to get out of it?

It was surprisingly useful in the early spring when there was a big difference in temperature, but we're not ready to use it in full-blown extreme heat yet. I'll have a review of the various summer situations I've tried it in and I'll tell you about it later.


This article is based on an article from the Japanese edition of Engadget and was created using the translation tool Deepl. The Japanese edition of Engadget does not guarantee the accuracy or reliability of this article.