It expands to about 10 times its size when placed in water. ^^ Material: Sodium polyacrylate [PSC Mark Certified] Complies with the technical standards set by the government, with a maximum size of less than 2cm. The color may appear different in the photos due to lighting conditions. Please understand that this item is stored at home. Thank you. m(_ _)m #BallList #1000YenItems #NostalgicToysList Children's Association, Children's Association, Event, Water Play, Festival Games, Festival, Present, Expanding Toy Gender...Unisex Toy Genre...Pool/Water Play Gender...Unisex Toy Genre...Pool/Water Play