Johnson's 40-6720 Universal Detector Kit includes a laser detector which is designed to work with most manufacturers red beam rotary laser. The detector allows a red beam rotary laser to be used outdoors or in high ambient light conditions or whenever the human eye cannot see the laser beam. This detector senses the broken pulsating light emitted from the rotary laser and quickly and accurately locates the laser signal being emitted from red beam rotary lasers even when the beams are invisible to the human eye.