The red lights are mounted around the machine to project a red border on the ground to alert bystanders to stay clear of the machine. Two blue lights are mounted to the front light guards to project dots where the bucket cutting edge contacts the ground. A blue light is mounted on the back hood to project a dot on the ground behind the machine when the machine is moving in reverse. Lights are not visible on the ground during daylight.For further details, reference media available at catpublications.com and SIS2.cat.com (M0165583) or contact your local Cat® Dealer.