Hydraulic Electromagnetic Valve

electromagnetic
Of or relating to the interrelation of electric currents or fields and magnetic fields
(electromagnetism) magnetism produced by an electric current; "electromagnetism was discovered when it was observed that a copper wire carrying an electric current can magnetize pieces of iron or steel near it"
Electromagnetism is one of the four fundamental interactions of nature, along with strong interaction, weak interaction and gravitation. It is the force that causes the interaction between electrically charged particles; the areas in which this happens are called electromagnetic fields.
pertaining to or exhibiting magnetism produced by electric charge in motion; "electromagnetic energy"

hydraulic
(of cement) Hardening under water
moved or operated or effected by liquid (water or oil); "hydraulic erosion"; "hydraulic brakes"
of or relating to the study of hydraulics; "hydraulic engineer"
Of or relating to the science of hydraulics
(hydraulically) in a hydraulic manner; "the block is then tested hydraulically to its full design test pressure on each stream separately"
Denoting, relating to, or operated by a liquid moving in a confined space under pressure

valve
A membranous fold in a hollow organ or tubular structure, such as a blood vessel or the digestive tract, that maintains the flow of the contents in one direction by closing in response to any pressure from reverse flow
a structure in a hollow organ (like the heart) with a flap to insure one-way flow of fluid through it
device in a brass wind instrument for varying the length of the air column to alter the pitch of a tone
control consisting of a mechanical device for controlling the flow of a fluid
A device for controlling the passage of fluid through a pipe or duct, esp. an automatic device allowing movement in one direction only
A cylindrical mechanism in a brass instrument that, when depressed or turned, admits air into different sections of tubing and so extends the range of available notes