Provides an easy visible indication of the relative disk position. Used when the valve is mounted in high or out-of-reach locations, but frequent monitoring of the valve position is required.

• 为相关的阀瓣位置提供便于观察的指示标志。用于当阀门安装在高处或无法靠近的地方时,但是有需要经常观察阀门开启位置的情况。