Abstract: An apparatus comprises a body, a first poppet, and a second poppet. The body comprises a first fluid channel and a second fluid channel. The first fluid channel and the second fluid channel are operable to be fluidly isolated from each other. The first poppet is positioned in the first fluid channel, and the first poppet is operable to be moveable within the first fluid channel. The second poppet is positioned within the second fluid channel, and the second poppet is operable to be moveable within the second fluid channel. The first poppet and the second poppet are operable to be mechanically coupled together such that movement of the first poppet within the first channel is operable to cause sympathetic movement of the second poppet within the second fluid channel.