The bosch gll 2 50bm professional line laser with wall mount bm1 and ceiling clamp comes complete in a l boxx advantages of the gll 2 50 professional laser precise lines high visibility self levelling horizontal and vertical pendulum line laser for quick alignment of lines and levels high visibility of the laser lines with a working range of 20 m without a receiver extremely precise in use with an accuracy of 3 mm at a distance of 10 metres vertical horizontal and cross line modes for precise a