... beam" Product model: DA208Y - 1 The alert level: three beams laser wavelength :980 nm (not visible) Warning distance: 0 ~ 1000 ... the basis fixed and no shift or shaking.Strong penetrating power of laser, very low rate of false positives, far prevent distance ... mines enterprises, large oil field oil depot, wharf, libraries, Banks, power, museums, exhibition halls, schools, farms, alert at the airport, ...