Self Test : Built in self test to ensure that the electronic components and logic circuits are functioning properly. System will go to wait state if the self test detect a malfunction and the two outputs will switch off.. Dual Electronic Circuits : with two separate outputs and feedback from each output to add the reliability and to ensure failsafe operations. Housing : extruded aluminium C Sections ensure that the product can withstand severe mechanical impacts. Mounting : "T" Slots allow for easy mounting arrangements. Optics : well designed optics ensure easy alignment. Optical Communication : No Interconnecting cables. Immune to noise.