Mighty Mule R4222 Pair of 12V Photo Eye Sensors Convenient added safety for your gate system to Avoid unwanted closure Easy DIY (DO it yourself) installation that includes 2 Photo beam sensors and mounting hardware Direct wired application to your Mighty Mule gate system (not compatible with solar powered gate opening systems) Required low-voltage wire (Rb509) not included; 100 ft., 250 ft. And 500 ft. Lengths available Backed by a 12 month Mighty Mule warranty and technical support