You get what you pay for. This is a cheap laser projector with three bubble levels and a metric scale. First, it's not self-aligning, so be careful when looking for it. Second, it is not possible to match the bubble levels to the projected laser lines. The two meters are independent. To provide a horizontal or vertical line, you must use an outside bubble level and center the beam on that level using the supplied or other (more stable) tripod. Third, the laser has very low power, so it cannot be used outdoors during the day. As far as I know it's only used to project a line longer than is normally possible with a standard physical layer. It can be used as a small three bubble spirit level and a short tape measure. It's impossible to determine the accuracy of a tape measure or three vials without secondary calibration reference standards, so I'll skip it. I would suggest (and that's a bad word) that this is the equivalent of a cheap tape measure or bubble level from Walmart or Harbor Freight.