Shower and tub-shower rough-in valves: the valve body that goes in the wall before it closes, in pressure-balance, thermostatic and multi-outlet configurations.
The rough-in and the finish trim are two separate purchases, and that is deliberate — the valve can be set during construction and the finish chosen months later. It also means the two must belong to the same manufacturer family. A Moen trim will not fit a Delta body, and cartridge families change between generations within a single brand.
Pressure-balance is the code minimum in most jurisdictions: it holds the hot-cold ratio when pressure drops elsewhere, which stops the scald when a toilet flushes. Thermostatic holds the actual outlet temperature and lets you set a number, which is what a multi-outlet shower needs.
Check whether the body includes integral stops. Without them, servicing the cartridge means shutting off the whole house.
Brands include Moen, Delta, Grohe and Brizo.
