The bosch gll 2 50 professional line laser amp bs 150 building tripod 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 due to single handed operation horizontal and ve