STAUFF FI-G-12L-W3-MS

In a hydraulic filtration setup, it serves as a filter indicator that signals differential pressure across the filter element. The point is to show when the filter is starting to load up so maintenance can happen before pressure drop starts hurting system performance.

Filter indicators like this one monitor the pressure difference across a filter element. When that differential gets high enough, the indicator signals that the filter is loaded up and needs attention. It keeps you from running a clogged filter too long, which can cause flow restriction or force fluid through a bypass. In hydraulic systems where filter condition matters for uptime, these get installed inline so operators or maintenance crews know when to pull and replace the element before things go sideways.