Fisher Whisper NXG trim for globe control valves allows you to use smaller valves where previously capacity limited without reduction in noise abatement, providing 20% more flow capacity than the market. Using the Whisper NXG trim cage in conjunction with a properly-sized valve body can substantially reduce the noise level of the control application. Aerodynamic noise is generated by the turbulence created in the flow of vapor, gas, or steam as the fluid passes through a control valve.