Fitting concealed shower body jets?

[eveares]

I am having a new shower fitted this week with concealed built-in body jets.

The trouble is the body jets came with no instructions and neither the builder or the plumber know how to fit them!

A drawing with dimensions of them is provided on the link below:

http://www.mfi.co.uk/images/tec_spec/Square-Body-Jet_4512.gif


Any idea how they should be fitted/mounted, plaster board and tileing is yet to go on, and what is the large nut for?

Any help much appreciated.

 

[Charnwood]

The big nut is to hold the jets in place and would be fitted inside the false wall. The flange to the right of it is the flange to go on the tiled side.

From the line drawing, if to scale, the jets are to be fitted to a surface roughly 10 to 12mm thick.