Yeah sure it can be just any. Do make sure that it is a land type Transmitter. Dont go out using a 72mhz or other air type transmitters. If you get a whole kit Transmitter, receiver, servos, and maybe the battery for a 4 ch its around 100 and some $ so make sure you make no mistakes with water leaks. Go to ServoCity they have some nice equipment there. Also the frequency can be 49 or 27 i guess if you could find one with 4chs. Servos it depends what you want. For a beginner you probably would watn to go with a dynamic diver. So you would need 2 servos. You could have a rudder and elevator setup or bowplanes and rudder setup either way works. Brass tubing is for waterproofing the shafts. If you look around on the web there are some water tight shafts with their own o-rings built in to their barings i think. It does not have to be brass but make sure whatever you use doesnt rust. For subs rust is bad. Pushrods are just the metal linkages that hook up to your servos which eventually would hook up to your control surface.