The Bosch LR Laser Receivers detect laser beams over extended distances, with visual and audible alignment signals for easy positioning . Models include LR 1 (rotation lasers, 200m range, IP65), LR 2 (combi/line lasers, 50m range, IP54), LR 6 (combi/line lasers, 50m range, IP54), and LR 7 (combi/line lasers, 50m range, IP54, detects green/red, large 8cm reception area) . All models feature fine/rough accuracy of ±1mm/±3mm. The LR 1 is powered by a 9V block battery (0.25kg) , the LR 2 by a 9V block battery (0.27kg) , and the LR 6 (0.12kg) and LR 7 (0.15kg) are powered by AAA and AA batteries respectively . Suitable for surveyors, civil engineers, and construction professionals.