<font color=blue>Is there some trick i'm not aware of or are they just good??</font color=blue>
In simple terms, they are just good but you have to remember, it's still just TV. /w3tcompact/icons/wink.gif
In reality, if you want to mount drywall on an already covered wall surface, they sell these things called stud finders in hardware stores and in places like that. I've never thought much of these things. A good drywaller can tell where the studs are just by tapping the existing wall surface and listening to the 'tone' of the knock to determine if he's hit a stud or empty space. The greater dangers though are a) if you have irregular stud framing different from the normal 15-16" stud separation (this is especially prominant in older houses 'done over' by inexperienced home improvers or when state building codes were not in place) and b) figuring out where the behind the wall electrical lines are running. You hit one of these lines by accident.....and this will require yet a bit more extensive wall rehab. /w3tcompact/icons/grin.gif
.....Bob