Your first step into the world of kairo is to just get a normal set of these self-heating pads. Don't be tempted to explore the other options until you get used to these as the temperature can get incredibly hot.

How do they work, you ask? The simple answer involves lightweight and breathable bags filled with iron powder. The iron, when exposed to oxygen, begins to rust, giving off the magical heat that we use to stay warm. The best way to enjoy these pads as the locals do is to keep one in each pocket. There, it's not only exposed to oxygen, allowing the reaction to continue, but the heat produced is contained within your pockets. So, leave your hands inside to conquer the bitter cold.

As the name suggests, these "magma" kairo pads are the way to move forward if the normal ones weren't hot enough. Boasting temperatures of up to 73 degrees Celsius (163.4°F), direct contact with the skin is not really recommended due to the potential of burning yourself. The best way to use these is to wrap them in a scarf before you head outside.

Once you have the right temperature for your pockets or your scarf, it's time to take care of your feet. You can find kairo to insert into the soles of your shoes to keep your feet nice and warm as you head out for the day. There are several varieties of these as well, from heating up your whole foot, just your toesies or the heel of your foot, or even the tops of your feet. Again, make sure to avoid direct contact with the skin to avoid burns, but as long as you are wearing socks or tights, you should be able to enjoy the heat worry-free!

Now it's time to reach out to all the other body parts that need the extra warmth! You can purchase kairo that have a sticky back, which allows you to attach the pads to any item of clothing. These are exceptionally good for joint or back aches as you can keep those areas warm during the winter. Again, ensure that these pads don't touch your skin directly. The ideal place to stick these pads would be the second layer of clothing, a t-shirt perhaps.

After a long day out in the cold, the nights can still be the toughest time to get warm; but, Japan has the answer to that as well! The eye mask kairo is here to ensure that your eyes are pampered with warmth to ensure a comfortable drift to sleep. These masks are lower in temperature as they are placed near a sensitive part of your face, so there is no need to worry about direct contact with the skin. But, the product claims to reduce wrinkles and give you a fresher look in the morning. And, there are lots of cute designs to make even your dreams stylish.