Greatly enhanced beam visibility for easier optical axis adjustment of sensors. The optical design maximizes the linear propagation of laser beams. Red laser beams (class 1) can be precisely aligned on the targeted position. The through-beam sensing distance of 60 m provides sufficient allowance, enabling Through-beam Models to be used with reliability even in dusty environments. With Through-beam Models, an emission interruption function is also available by request. This function is ideal for preventive maintenance applications.