The size is approximately 30cm wide x 22cm tall. This is a seat cushion using R-value 4.0 high-insulation American-made Reflectix. (Compared to Astrofoil E with a single air layer, it offers incomparable insulation and cushioning.) As shown in the second image, the fun difference from other insulation mats is that you can put your favorite stickers on it. Due to its high insulation performance, it is also effective for placing under the feet of those who have cut their Yamatomichi or Evernew mats short. I have cut it to various sizes, but considering the size when folded in half, I have slightly reduced the size to a comfortable range. It is useful when you don't want to sit directly on a frozen bench or wet ground, or when you don't want to place your backpack on wet ground. It is a high-tech sheet with a 7-layer structure including 2 layers of air bubble layers, providing excellent cushioning. As shown in the third image, it can be folded in half and quickly stored in a backpack pocket. It can be wiped clean easily, and sand can be brushed off with a flick. By folding the dirty side inward, it can also be stored inside your backpack.