Are there any other adaptors needed for Letus?
 

I am looking at hiring a Letus Extreme kit from a friend. I'm not sure what camera he uses it on, but I do know that he doesn't have a 77mm adaptor for it. If I were to buy my own 77mm adaptor do I need anything else to be able to use it?

you'll need
 

ex1/3 optimazation kit. adapter for lenses you will be using (nikon, canon...)
and a lens support kit to minimize stress on the cam/lens/adapter... i.e. rods etc...