High accuracy. The symmetrical arrangement of the multi-hole ensures the flow profile to be steady and conditioned thus reducing the turbulence effect. Life time is 5-10 times longer than the traditional throttling devices; Shorter straight pipe. In most cases, the length of straight pipe can be as short as 0.5D-2D; Low Permanent Pressure Loss. Symmetrical structure decrease the formation of vortex flow and turbulence friction, saving the running cost; Wide flow range. Range ratio can improve to 20:1 - 30:1 if appropriate parameter is selected; Repeatability and Long-Term Stability. Balance the flow field, and improve the repeatability.