The bosch gll 2 50 professional line laser amp bm1 wallceiling mount lr 2 laser receiver and bt 350 telescopic pole gives you precise lines and high visibility self levelling horizontal and vertical pendulum line laser for quick alignment of lines high visibility of the laser lines with a working range of 20 m without receiver extremely precise in use with an accuracy of plusmn3 mm at a distance of 10 m vertical horizontal and cross line modes for precise alignment easy handling d