The indicator post is used to control the underground fire service mains. It comes with a window sign to indicate whether the valve is open or closed. The opening wrench supplied can be locked to the indicator post to prevent unauthorized operation. Three standard length posts can be supplied to suit the bury depth. Field adjustments can be made by simply cutting the top of the stem to suit the post length.Model Size Bury Depth (mm) Material NPI-100 4" 1385