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Mount the two electric eye sensors on either side of the garage door opening, approximately six inches (15 cm) from the ground. These sensors emit and receive an infrared beam. Use an impact driver to secure the mounting brackets, then attach the sensors. Route the low-voltage wiring from each sensor through a plastic conduit for protection, leading it up the wall and over to the opener unit. Connect the wires from both sensors to the designated terminals on the garage door opener. The sensors must be aligned so that the beam between them is unbroken; if the beam is interrupted, the door will not close or will reverse if already closing, providing crucial safety.