Final answer:
A post indicator valve (PIV) uses a pointer and graduated scale to show the position of the valve.
Step-by-step explanation:
On a post indicator valve (PIV), the position of the valve is shown through a pointer and a graduated scale.
A post indicator valve (PIV) is a type of valve used in fire protection systems to control the flow of water from the main water supply to the fire protection system. The valve has a pointer attached to its stem, which moves as the valve opens or closes. The position of the pointer indicates the status of the valve, whether it is open or closed.