ok..I read all the reviews and just dont get their raving over this product.If you can hold it down right it works but this is not that easy when it is over your head. For those of you who dont know how this thing works here is a quick run down. hold the top portion on the wall. Not over a stud because it calibrates when it turns on and if it is on a stud then it will read wrong. The top and the bottom section swivel independant from each other . you hold the top next to the wall and push down on the bottom and it turns on. if you lift the bottom just a little it turns off and you have to start over. I think the Ziroc scanner are a good product just not this setup.I returned mine and got the model a step down that is all one case and doesnt swivel.