A pulsating beam turns on for 90 seconds when the IR beam is interrupted. * The driver pulls the car in until the red dot from the laser hits a pre-targeted spot on their dash. * Simply connects to the photo-eye (IR) terminals of any LiftMasterTM Garage Door Opener. * Two laser parking accessories may be installed with each garage door opener. * Class 2 laser is safe on the eyes, yet clearly visible.