The bosch gll 2 50 professional line laser bm1 wallceiling mount 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 20m without receiver extremely precise in use with an accuracy of plusmn3 mm at a distance of 10m vertical horizontal and cross line modes for precise alignment easy handling due to single handed operatio