Differential pressure gauges measure the difference in pressure between two points in a system. Dial differential pressure gauges have an analog dial and back, side, or inline process connections. Digital differential pressure gauges have an LCD display with back, side, or inline process connections. Digital differential static pressure transducers measure differential pressure of static flow. Both analog and digital models may be available with an electrical switch to interface with a control. Tricolor differential pressure indicators have a color-coded zones to show if the filter is in need of cleaning or replacement.