Panasonic SF4B series combines PNP transistor output and NPN transistor output in a single model. Overseas equipment that uses PNP, replacement with NPN sensors, factories that are positively grounded, and transfer of equipment overseas are all situations where the control circuits for a single model are suitable for use worldwide. Can be widely used for press machines and other types of equipment from Japan, Europe, North America, South Korea, and China. A seamless structure with minimal joints has now been developed.The inner unit is protected by a cylindrical inner case. Seams on the unit and lens surfaces have been greatly reduced so that particles such as oil mists and dust are prevented from penetrating the case. Thus, the environmental resistance performance could be raised. The system constantly checks the light curtain for problems such as incorrect cable wiring, disconnection, short-circuits, internal circuit problems, and incoming light problems. Details of any electrical problems such as at equipment startup will appear on the digital display. It is no longer necessary to count the number of times the LED blinks, making the system much more convenient.