Chipboard (cardboard) Color: Both sides white Thickness: 0.6mm Size: A3 Quantity: 100 sheets I previously purchased these in bulk from Matsumoto Paper Store, but I didn't use them all and have leftovers. They are packaged in units of 100 sheets, so the outer packaging is slightly torn, but they are unopened. I have included photos of the same product that I have opened and used for reference. Although unopened, please understand that these have been stored at home for a long time before purchasing. (Since the opened product is the one in the photo, I believe there is no noticeable deterioration.)