The head is pretty robust but as with anything, once some with a screwdriver decides to open it all bets are off. You need to know what you are doing to re-assemble the mechanism. Usually one can tell if someone clumsy has opened it as the screw heads show it.
There are two different power supplies. The older one is just a box with the transformer in it. Simple and reliable. The newer one is the Chromegatrol, with a built-in digital timer. Whichever one you get, make sure it works. To mount the head in place of a condenser head, you need two longer rods you can get from the hardware shop. The rest of the mounting hardware from the condenser head can be re-used.