you had better have shut off valves behind that shower unit
cause once you are into it , you are into it for the long haul
finding pricefister parts could be a major problem
hunting high and low for them ect......they can be nearly impossible
to get parts for in a timely manner......
so be sure you can get the faucet to shut off first or you
might have to shut off the whole house till you are able to make the
repairs....or change out that faucet...