Apparatus for measuring the differential group delay \u03c41 in an optical fiber connection. In the suspension apparatus, a hydraulic damper is disposed between an electromagnetic actuator and a wheel-holding portion, and a cover tube is provided for accommodating a seal provided between a piston rod and a housing of the hydraulic damper. Each foil member is mounted to a pivot shaft for limited rotational movement with respect to the vehicle body. Additional embodiments are disclosed. The batten riser assembly is designed to prevent the damming of water that penetrates the tile roof.