Precise laser lines and high visibility with the gll 2 50 working range of up to 20m without a receiver and up to 50m with a receiver the gll 2 50 allows horizontal and vertical self levelling up to 4 the ability to interchange between vertical horizontal and laser cross lines allows for precise alignment in many applications the gll 2 50 is extremely precise in use with an accuracy of 3 mm at a distance of 10m