Want to be the life of the party? This inflatable T-Rex costume is hilarious! You just step in, turn on the fan (powered by 4 AA batteries - not included, or use a power bank via USB), and it puffs up in seconds. It's made from lightweight polyester, so it's breathable and easy to move in. Perfect for Halloween, costume parties, school events, or just goofing around. The fan and battery pack are built into the costume. It's a surefire way to get laughs and make memories. One size fits most adults and teens. Get ready to stomp around as the coolest dinosaur ever.