And laser levels have in the middle of the installed laser equipment that issues a laser beam that displays the point on the plane against the level, or, when using the prism, shows a whole line. Further, a vertical or horizontal surface is applied between the level and the rail. In the use of laser levels, a great advantage is good visibility, as well as the possibility of simultaneous use at several points, in addition to the main zone, plus the possibility of simultaneous marking of several different planes.