designer's own words:‘My costoby’ has the meaning of ‘my pocket’. ‘costoby’ means pocket and when ‘my’ comes before it this means reservoir for individuals – private refrigerator. The motive for making this product is as follows: when I was outside drinking warm water and when I felt the difficulty in keeping food cool in the mountains and fields, I started thinking of ways to overcome this discomfort. This product is designed for people working outside of homes. It has semiconductor cooling technique, but it is light enough. The user can easily attach it to the climbing bag or backpack through the hole which holds strings. Even if the user does not have a bag, one can wear it comfortably on one’s back or waist since this equipment has a streamline shape and flexible materials. This product has a door on the front side; power switch and temperature dial on the top. On the bottom is the terminal used for recharging and many holes to hold strings are places on the back. On the both sides are transparent windows made out of rubber so that the user can check what’s inside. The quantity of this refrigerator is about 1L, which means it can hold two water bottles of 500mL. This size will be suitable for an individual usage.