Thick paper, crimson Size: Amateur measurement 18.1 x 18.1 cm, thickness 1 mm, material Since it is hard paper with a thickness of 1 mm, you can sandwich it with things you don't want to bend... Various uses such as handmade crafts Thick paper for mini books, etc... 25 sheets make 1 set. There are 5 sets in total, so please comment if you wish to purchase multiple sets.