Abstract: An air actuator adapted to be located between a pair of spaced members for moving said members with respect to each other includes a hollow body formed of an expandable non-reinforced polyurethane. The body has an ellipsoidal shape and terminates in a pair of curved closed ends and has an interior pressure cavity for receiving and discharging a pressurized fluid for expanding and contracting the body. The body is formed of at least two half members of the non-reinforced polyurethane by either a pair of longitudinal seams extending generally parallel to a longitudinal axis of the body or a single circumferential seam. An air tube connector is mounted in one of the closed ends of the body for connecting the interior cavity to a source of pressurized air.