The bosch gll 2 50 professional line laser amp bm1 wallceiling mount lr2 laser receiver with l boxx 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 hande