
The one I received seems accurate, I find the single knob easy to use. The screw attachment at the base of the spirit level is not flush with the other legs, so it will wobble a bit when placed on a perfectly flat surface. But the auto-level feature solves this problem. The only thing that confuses me is that the laser beam is weak. In a 25' x 20' covered basement with the lights on (it's a fairly well-lit basement) it's difficult to see the light on the walls. If I dim the lights or only turn on a few, it's ok. So it's a good tool where to use it, but there are limitations where to use it.