William Mark Air Swimmers swim through the air with incredibly smooth and life-like swimming motion. Accept no imitation, this is the authentic William Mark Air Swimmer Shark and Clown! These amazing fish provide hours of remote control indoor fun in even the smallest of rooms (not for outdoor use). They require only four AAA batteries (one in the body, three in the controller) and have complete up, down and 360 degree turning control. The Shark and Clownfish is remote infra-red controlled and will respond to your inputs moving up and down most importantly left to right with fish like tail movement. Remote control has never come to life so magically! The helium filled fish body is made from durable nylon and with appropriate use will stay inflated for weeks depending on altitude. The William Mark Corporation has been dedicated to developing unique, high-quality products for extraordinary flight performance. The company was formed when Mark Forti, then a junior at Baylor University in Waco, Texas, invented the X-zyloTM for a marketing project. The product's performance amazed everyone who saw it. After stumping his physics professor as to why the object flew, Mark took it to his father, William, who worked in the aerospace industry. When William's aerodynamicist friends could not explain how it flew so far, William and Mark filed for patents and formed the William Mark Corporation.