An initiator assembly that includes an initiator and a containment shell. The device comprises a clip adapted to be detachably secured about the conduit section. Each light source emits light at a different wavelength spectrum which is selected to enhance the display of the fluorescent object under each type of external lighting condition. In one non-limiting embodiment, no added hydrogen is employed. The latching unit may precharge first and second nodes in response to a clock signal and controls voltage levels of the first and second nodes in response to a sensing result of the sensing unit. Further, the width of each of the column-shaped members 32a along a direction perpendicular to the gas-flowing direction is in a range of 0.