The present invention provides apparatus and a method for projecting an indication of alignment. The invention features forming a first output beam, and a second output beam that is substantially perpendicular to the first output beam. The first output beam indicates level, the second output beam indicates...http://www.google.fr/patents/US6763595?utm_source=gb-gplus-shareBrevet US6763595 - Laser-based tool for indicating level, plumb and square
Laser-based tool for indicating level, plumb and square
