Parker Proportional Hydraulic Valves

hydraulic valves
(Hydraulic valve) Irrigation zone valve which uses small flexible tubes and water under pressure to provide the actuation signal from the controller to the valve.
(Hydraulic Valve) In the construction of hydraulic elevators, a valve used to regulate the flow of the fluid used to raise and lower the elevator, usually a low viscosity oil.

proportional
Corresponding in size or amount to something else
properly related in size or degree or other measurable characteristics; usually followed by `to'; "the punishment ought to be proportional to the crime"; "earnings relative to production"
having a constant ratio
one of the quantities in a mathematical proportion
(of a variable quantity) Having a constant ratio to another quantity

parker
Charlie (1920–55), US saxophonist; full name Charles Christopher Parker; known as Bird or Yardbird. From 1944, he played with Thelonious Monk and Dizzy Gillespie and became one of the key figures of the bebop movement
United States saxophonist and leader of the bop style of jazz (1920-1955)
United States writer noted for her sharp wit (1893-1967)
This article lists characters and actors in the Alien series of science fiction films. The series spans four films: Alien (1979), Aliens (1986), Alien 3 (1992), and Alien Resurrection (1997).