Make sure you purchase the correct valve for the faucet you're planning to install in your shower. It should have two inlet channels for the hot and cold water, and two outlet channels for the tub spout and shower head. Each of these fittings connects to your pipe either through male threads on the outside or female solder ports on the inside. If your bathroom has either a tub or shower only, then the second outlet channel will need to be capped off in the installation. Shower only valves are also available for bathrooms without a tub. The valve itself must come out the correct distance from the wall and is mounted to a stringer, which is a brace running between the studs. Allow for the depth of the valve, the water-resistant drywall, and the thickness of the tile or shower enclosure when setting the proper depth for the stringer. The instructions that come with the valve will show the correct dimensions for the valve and its plumbing.
Homedepot
59 second
landscape
low
Brown,Khaki,Olive,Brown,Orange,Khaki,Cream
shows a water pipe is sitting on a table in a room
boredom, comfort
1
indoor
brass, lamp, ceiling, closet, copper, hook, tool
neutral
Olive,Gray,Dark_Gray,Gray,Olive
shows a towel sits on the edge of a bath tub
comforting, comfortable, comfortable
2
product
bath, bathroom, bathroom accessory, floor, green, wall lamp, shower, towel, towel bar, tub, white, yellow
neutral
Low
shows 
3
Off_White,Cream,Olive,White,Pink,Dark_Brown,Brown,Tan
shows a close up of a gold toilet fixture
comfort,
4
product
bolt, brass, close-up, copper, knob, lens, nut, screw, tool, valve
neutral
Low
Light_Blue,Lavender,White,Light_Blue,Dark_Blue,Dark_Gray
shows the inside of a white wall with a white tiled bathroom
comfortable, improvement
5
business
bathroom, bathroom accessory, toilet paper, close-up, door handle, handle, knob, lock, photo, white
Step 5: Choose a New Valve'
cool
Low
Olive,Black,Dark_Brown,Brown
shows a wooden post with a brass lamp sitting on it
comfortable, relaxing
6
product
attach, camera, camera lens, lens, pole, telescope, tripod, video camera
neutral
Low
Mud_Green,Dark_Gray,Black,Brown,Dark_Brown,Brown,Off_White
shows a valve showing a metal plug and a gold and copper pipe
dirty,
7
indoor
attach, brass, copper, door handle, tool, valve
neutral
Low
Light_Blue,Lavender,Gray,Olive,Mud_Green
shows a photograph of a camera with a camera body and lens
comfort, comfort, care
8
product
door handle, white
cool
Low
Mud_Green,Brown,Khaki,Dark_Brown,Brown,White,Khaki
shows a valve attached to the side of a wood beam
pressure, comforting
9
product
attach, brass, plank, tool, valve, wood
neutral
Low
Gray,Lavender,Light_Blue,Dark_Brown,Dark_Red,Dark_Gray,Black,Gray
shows an iron plumbing fixture being fixed on a wall
comforting, care
10
copper, pipe, tool, valve, writing
920:40
neutral
Low
All you need to know: Bathroom valves