A retainer employs a flexible arm with an internal rib. Based on an operational instruction in response to a driver’s operation, a rotational speed reducing instruction is given to the engine control unit for reducing an engine rotational speed set by the engine control unit by a predetermined amount. Furthermore, another object of the present invention is to provide a new established cell line expected to be used in the diagnosis of viral infection disease of sturgeon and so on. The seat suspension and the first bumper element are arranged to adjust a length of the protruding portion. A control valve concentric to the actuator cylinder tube is configured to be coupled to a source of pressurized fluid and controls admittance of the fluid under pressure to the actuator cylinder at the second cylinder end to act on the actuator piston rod to extend the actuator piston rod towards the first cylinder end. , includes a cover protecting the principal part of the object, and at least one protective covering for at least one component movably affixed on the object.