Heeeeeeeey Arnold – that’s a great Hey Arnold Gerald Hat! The Nickelodeon Snapback Hat is inspired by Gerald on the popular, 90s Nickelodeon Cartoon, Hey Arnold! The Hey Arnold Hat features bold, embroidered front art inspired by Gerald's hat from the cartoon. The Nickelodeon Hat is made of acrylic wool material that is comfortable, durable, and easy to care for. The Hey Arnold Apparel features a snapback feature that easily fits most sizes and the hat is 58cm.