A wireless key includes a receiver circuit that operates with a built-in battery, and receives a polling radio wave for wireless key search and authentication from a vehicle, and a transmitter circuit that transmits a lock operation radio wave to a door based on the manipulation on a manipulation device. The rotatable module is pivotally disposed in the cavity. The bracket is carried or trapped between adjacent layers of the composite material so that the bracket is fixed to the tank. The covering material is sized and configured to cover the controller in manner that the user has access to the controller’s action control buttons and the selection control buttons. The rack step tool may further have a securing element such as a hook for insertion into another hole in the support member for further securing the rack step tool thereto. The housing includes a chamber with an inlet port and an outlet port.