My main complaint is that the instructions are very thin, not to mention the grammatical problems of the English language. If someone is working alone, say, hanging several paintings in a row on the same plane from 2 sides, how can you mark the places if the device does not have the ability to hang it on the wall, freeing at least one hand around then mark the spots to hang other frames. Also, if I'm not mistaken, how is it possible to level, for example, a table saw fence when the device is on its back and you get an ERR message. I do not understand that. At the moment I cannot recommend this product in terms of use or value for money.