The DeWalt DW082K Self-Leveling Laser Plumb Bob kit is just the right tool for providing accurate plumb reference. Two laser beams plumb up and plumb down, project two bright dots. The self-leveling laser plumb bob is accurate to ±1/8 @ 50. The accuracy level is such that, after the spots on the floor and ceiling are marked as indicated by these dots, when rotated in 90-degree increments for a full 360 degrees, the laser dots precisely zero-in on the marked spots.It self levels reasonably quickly, and the out-of-level sensor alerts if it is positioned out of its self-leveling range. Lights and fans can easily be installed even on sloped ceilings, using this dewalt Plumb tool. The overhang of the frame gives good visibility of the lower dot for reference or marking purposes.The DW082K can be used to plumb walls, during stick framing and even to locate the end of the top plate of a wall. Simple to operate, the cross-hair beam pattern makes it easy for the user to find the center of beam, and the magnets help to conveniently attach this surveying equipment to metal tracks. Features: Accurate to within 1/8-inch over 50 feet for precise marking One-button, self-leveling design saves time and eliminates errors Focused beams deliver small, bright dots for improved visibility and accuracy Cross hair beam pattern makes it easy to identify the center of each beam What's In the Box: DeWalt DW082K Laser Plumb Bob