A connector with a structure having a tip of a body holding a first contact set is located in an opening formed by a shell member including a shell and a shield cover. Each cylinder is provided with an intake port and a fuel injector to inject fuel in the intake port and repeatedly performs an intake stroke, compression stroke, expansion stroke and an exhaust stroke. The data receiver includes a command receiver, and an ACK transmitter. The reference voltage is determined readily and accurately, the flow meter measures the flow rate with the appropriate reference voltage. Air cooled by the luminaire is allowed to sink and may flow out of the luminaire via a gap between the heat sink and the luminaire.