HI
I use Hilti laser levels........a couple of different types, the first is Hilti's latest which projects either a single straight line (horizontal or vertical) or with a cross and is self levelling.......no messing about fiddling to adjust. I'ts quite small and comes with various attachment options eg: tri-pod, magnetic clamp, door frame fixing and scaffold clamp bracket. Also in the case are a pair of infra-red type glasses (which are fantastic to see the laser line in bright light) and a special
tile pencil.
The second type is also a Hilti and again is self levelling but this one is like a little robot which projects a small dot both on the walls, ceiling and floor. This dot can be made to spin around the room very fast and also comes with a special catcher card that allows you to stop the laser dot so you can mark the datum line. This level is easily operated by one person and will project a line at great distances ideal for large factory units.
Hilti tools are not cheap and don't claim to be but they are highly callibrated for accuracy and their guarantee's are second to none. Worth taking a look at guy's:yes: