A laser line level is a tool combining a spirit level and/or pendulum with a laser to indicate a levelled line against a surface.

Handheld laser line levels are used in surveying, construction and cabinetry industries.

In surveying, the laser level is affixed to a tripod, levelled and then spun to create a horizontal plane. The laser beam projector employs a rotating head with a mirror, for sweeping the laser beam in a horizontal plane, with visually readable level vials and manually adjustable screws being provided for orienting the projector in a level attitude so that the beam plane is level.

References

• Rando, et al "System for controlling attitude of laser beam plane", US Patent 4,062,634, December 13, 1977.