these are a joke. the arm shapes are not as pictured. some sockets were not assembled to the arms. there are not the right parts to mount to electrical box.  the arms have to be assembled at angles or they run in to each other, because not all of them are the right shape. i am a mechanical engineer. I did not assemble them wrong. i assembled them the only way possible. couldn't send them back as i painted them before assembly. don't buy these.